Operator's Manual AT, MT, HT Series Allison AT MT Transmission

User Manual: Allison-AT-MT-HT-Transmission M939 Series Trucks

Open the PDF directly: View PDF .
Page Count: 48

Operator’s Manual

AT, MT, HT Series

On-Highway Transmissions

OM1334EN

i

OM1334EN

July, 1997

Revision 2 20000501

Operator’s

Manual

Allison Transmission

AT 540

AT 542(N)(R)(NFE)

AT 543

AT 545(N)(R)

AT 1542P

AT 1545P(N)

MT 640, MT(B) 643, MT 643R, 644, 647

MT 650, MT(B) 653, 654CR

HT 740(D)(RS)(FS)

HT 747(D)

HT 750CRD, HT 750DR (DB)(RS)

HT 750DRI, HT 750DRD (DB)

HT 754CRD, HT 754CR (RS)

Printed in U.S.A. Copyright © 2000 General Motors Corp.

Division of General Motors Corporation

P.O. Box 894 Indianapolis, Indiana 46206-0894

ii

WARNINGS, CAUTIONS, AND NOTES

IT IS YOUR RESPONSIBILITY to be completely familiar with the warnings and

cautions described in this handbook. It is, however, important to understand that these

warnings and cautions are not exhaustive. Allison Transmission could not possibly

know, evaluate, and advise the service trade of all conceivable ways in which service

might be done or of the possible hazardous consequences of each way. Consequently,

Allison Transmission has not undertaken any such broad evaluation. Accordingly,

ANYONE WHO USES A SERVICE PROCEDURE OR TOOL WHICH IS NOT

RECOMMENDED BY ALLISON TRANSMISSION MUST first be thoroughly

satisfied that neither personal safety nor equipment safety will be jeopardized by the

service methods selected.

Proper service and repair is important to the safe, reliable operation of the equipment.

The service procedures recommended by Allison Transmission and described in this

handbook are effective methods for performing service operations. Some of these

service operations require the use of tools specially designed for the purpose. The

special tools should be used when and as recommended.

Three types of headings are used in this manual to attract your attention. These

warnings and cautions advise of specific methods or actions that can result in personal

injury, damage to the equipment, or cause the equipment to become unsafe.

NOTE:

A note is used when an operating procedure, practice, etc., is

essential to highlight.

WARNING:

A warning is used when an operating procedure, practice,

etc., if not correctly followed, could result in personal injury or loss of life.

CAUTION:

A caution is used when an operating procedure,

practice, etc., if not strictly observed, could result in damage to or

destruction of equipment.

TRADEMARK INFORMATION

DEXRON

®

is a registered trademark of General Motors Corporation.

iii

TABLE OF CONTENTS

Page

INTRODUCTION

Warnings, Cautions, And Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii

Keeping That Allison Advantage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Typical AT, MT, And HT Model Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . 2

A Brief Description Of The Allison Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Torque Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Lockup Clutch (AT 1500, MT(B) 600, HT 700) . . . . . . . . . . . . . . . . . . . . . . . . . 3

SHIFT SELECTORS

Allison Automatics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Typical AT, MT, HT Shift Selector Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Range Selection — AT 500 Series And AT 1500 Series With A Second

Neutral (Park) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Range Selection — AT 500 Series And AT 1500 Series Without A Second

Neutral (Park); MT 640, MT(B) 643, MT 643R, MT(B) 644, MT 647;

HT 740, HT 747. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Range Selection — MT 650; MT(B) 653DR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Range Selection — HT 750CR, HT 754CR, MT(B) 654CR . . . . . . . . . . . . . . . . 13

Range Selection — HT 750DR, HT 750DR DB . . . . . . . . . . . . . . . . . . . . . . . . . 15

DRIVING TIPS

Throttle Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Downshift Inhibit Feature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Operating In Cold Weather. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Using the Engine For Downhill Braking To Slow The Vehicle

Or Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Using The Hydraulic Retarder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Auxiliary Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Two-Speed Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Towing Or Pushing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Parking Brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Driving On Ice Or Snow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Rocking Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Temperatures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

iv

Page

POWER TAKEOFF OPERATION

Engine-Driven PTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Converter-Driven PTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

CARE AND MAINTENANCE

Periodic Inspections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Prevent Major Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Importance Of Proper Fluid Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Transmission Fluid Check Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Cold Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Hot Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Dropbox Fluid Check Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Keeping Fluid Clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Recommended Automatic Transmission Fluid And Viscosity Grade

Non-MT 643R Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Recommended Automatic Transmission Fluid And Viscosity Grade

MT 643R Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Fluid And Filter Change Intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Fluid Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Auxiliary Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

CUSTOMER SERVICE

Owner Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Service Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Allison Transmission Distributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Allison Transmission Regional Offices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

1

KEEPING THAT ALLISON ADVANTAGE

Allison automatics provide many advantages for the driver who must “stop and go” or

change speeds frequently. Driving is easier, safer, and more efficient.

These automatics are rugged and are designed to provide long, trouble-free

service. This handbook will help you gain maximum benefits from your Allison-

equipped vehicle.

HILL

HILL

SPEED

ZONE

RR

STOP

YIELD

YIELD

V01724

INTRODUCTION

2

TYPICAL AT, MT, AND HT MODEL TRANSMISSIONS

AT Model Transmission

MT Model Transmission

HT Model Transmission

3

A BRIEF DESCRIPTION OF THE ALLISON AUTOMATIC

Allison automatics described in this manual include a hydraulic torque converter, a

planetary gear train, and a hydraulic control system which supplies fluid under

pressure to apply the clutches and automatically shift ranges.

The torque converter multiplies engine torque during starts and acts as a hydraulic

cushion between the engine and gearing. The clutches and gear sets provide multiple

speeds forward and one speed reverse.

The torque converter lockup clutch, for maximum fuel economy, engages

automatically after the vehicle is moving. All models in this manual, except AT 500,

have a lockup clutch.

TORQUE CONVERTER

The torque converter consists of three elements — pump, turbine, and stator. The

pump is the input element and is driven by the engine. The turbine is the output

element and is driven by fluid from the pump, or directly by the pump when the

lockup clutch is engaged. The stator is the reaction (torque multiplying) element.

The torque converter is continuously filled with fluid. The pump, driven by the engine,

directs the fluid against the turbine vanes, which causes the turbine to rotate. The

turbine returns the fluid through the stator, which redirects the flow so that fluid strikes

the pump vanes in the same direction that the pump is rotating. As the pump turns

faster in relation to the turbine, the velocity of the fluid increases and so does the

torque multiplication.

As the speed of the turbine approaches the speed of the pump, the fluid flow starts

striking the back sides of the stator vanes. This causes the stator to freewheel in the

same direction as the pump and turbine. When this occurs, the torque multiplication

stops and the converter functions as a fluid coupling.

LOCKUP CLUTCH (AT 1500, MT(B) 600, HT 700)

The lockup clutch consists of three elements — piston, clutch plate, and backplate.

The piston and backplate are driven by the engine. The clutch plate, located between

the piston and backplate, is splined to the converter turbine.

The lockup clutch automatically engages after the vehicle is moving and the torque

multiplication demand is low. Engagement of the lockup clutch mechanically

connects the torque converter pump to the turbine and provides a direct drive from the

engine to the transmission. The lockup clutch automatically releases at lower vehicle

speeds. When the lockup clutch is not engaged, drive from the engine is transmitted

hydraulically through the converter to the transmission gearing.

4

Because the converter lockup engagement and release are designed to fit the vehicle’s

vocation, there are many variations among transmission assemblies. Lockup speeds

are determined by many factors. Among these are transmission-engine match,

transmission-vehicle match, model year, throttle position, and calibration of the

hydraulic system. Some models have lockup available in all ranges. Others have

lockup available in the upper ranges. Some models have modulated lockup, which

provides better engine braking by delaying lockup disengagement during closed-

throttle operation. For specific information on the lockup characteristics of your

transmission, contact your dealer or distributor.

Lockup engagement, like range shifts, may be felt under some conditions. The driver

who counts shifts should not confuse lockup with a range change. A little driving

experience with the Allison automatic will enable the driver to distinguish between the

two kinds of shifts.

5

The vehicle manufacturers may choose different types of shift selectors for their

equipment. Different transmission models may also require different designations on

the shift selectors.

Typical Shift Selector Labeling

These are some of the typical shift selectors you may find in Allison-equipped

vehicles. The range selector in your vehicle may vary from these or may have

1

(First Range) at the top and

R

(Reverse) at the bottom. Some models may have

a

P

(Park) position.

The best performance will be obtained by using the correct range for each driving

condition. The following table illustrates shift patterns for the various models and

indicates the page that explains the shift pattern for your vehicle.

R

N

D

4

3

2

1

R

N

D

3

2

1

R

N

D

2-4

2-3

2

1

R

N

D

2-4

2

1

V01958.01

SHIFT SELECTORS

6

ALLISON AUTOMATICS

Typical AT, MT, HT Shift Selector Positions

When your vehicle is equipped with an Allison automatic, it is not necessary to select

the right moment to upshift or downshift during the changing road and traffic

conditions. The Allison automatic does it for you. A knowledge of the ranges available

at your shift selector will make control of the vehicle and your job even easier.

When the shift selector has no

P

(Park) provision, always put the selector in

N

(Neutral) and apply the parking brake (or service brakes if the vehicle is not

equipped with a parking brake) to hold the vehicle when it is unattended and before

turning off the engine.

* Available on AT 500 Series and AT 1500 Series models

only

(refer to Page 7).

+ This position not present on models with

P

(Park).

** Optional.

◊

Without second gear start.

AT 500

Series And

AT 1500

Series

MT 640,

MT(B) 643,

MT 643R,

MT(B) 644

◊

,

MT(B) 647

MT 650,

MT(B)

653DR

HT 740,

HT 747

HT 750CR,

HT 754CR,

MT(B) 654CR

◊

HT 750DR

(DR DB)

Park — — — — —

Reverse Reverse Reverse Reverse Reverse Reverse

Neutral Neutral Neutral Neutral Neutral Neutral

1–4 1–4 2–5 1–4 1–5 2–5

1–3 1–3 2–4 1–3 1–4 2–4

1–2

+

1–2 2 (2–3**) 1–2 1–3 2–3

1 1 1 1 1–2 2

———— 1 1

(Pages 7-10) (Pages 9-10) (Pages 11-12)(Pages 9-10) (Pages 13-14) (Pages 15-16)

P*

R

N

V01959

7

RAN

GE SELECTION — AT 500 SERIES AND AT 1500 SERIES WITH A

SECOND NEUTRAL (PARK)

P

This activates the vehicle parking brake and at the same time puts the

transmission in neutral. Use this position when you start the engine. If the

engine starts in any other position, except

N

(Neutral), the neutral start

switch is malfunctioning.

R

Use this to back the vehicle. Completely stop the vehicle before shifting

from a forward range to

R

(Reverse) or from

R

(Reverse) to a forward

range. The reverse warning signal is activated when the shift selector is in

this position. Reverse has only one range. Reverse operation also provides

the greatest tractive advantage.

N

Neutral position is used during stationary operation of the power takeoff

(if your vehicle is equipped with a PTO).

D

The transmission will initially attain 1st range and, as vehicle speed

increases, the transmission will upshift to 2nd range, 3rd range, and 4th

range automatically. As the vehicle slows down, the transmission will

downshift to the correct range automatically.

WARNING: If you leave the vehicle and the engine is running, the

vehicle can move suddenly and you or others could be injured. If you

must leave the engine running, do not leave the vehicle until you:

• Put the transmission in N (Neutral)...and

• Apply the parking brake and emergency brakes and make sure they are

properly engaged...and

• Chock the wheels and take any other steps necessary to keep the

vehicle from moving.

WARNING: If you let the vehicle coast in N (Neutral), there is no

engine braking and you could lose control. Coasting can also cause

severe transmission damage. To help avoid injury and property damage,

do not allow the vehicle to coast in N (Neutral).

WARNING: If you just downshift or just use service brakes when going

downhill, you can lose control and cause injury and property damage. To

help avoid loss of control, use a combination of downshifting, braking,

and other retarding devices. Downshifting to a lower transmission range

increases engine braking and helps you to maintain control. The

transmission has a feature to prevent automatic upshifting above the

lower range selected. However, during downhill operation, if engine

governed speed is exceeded in the lower range, the transmission may

upshift to the next higher range. This will reduce braking and could

cause a loss of control. Apply the vehicle brakes or other retarding

device to prevent exceeding engine governed speed in the lower range

selected.

8

RAN

GE SELECTION — AT 500 SERIES AND AT 1500 SERIES WITH A

SECOND NEUTRAL (PARK)

(cont’d)

3

2

Occasionally, the road, load, or traffic conditions will make it desirable to

restrict the automatic shifting to a lower range. (When conditions

improve, return the selector to the normal

D

(Drive) position.) These

positions also provide greater engine braking for going down grades (the

lower the range, the greater the braking effect).

1

Use this range when pulling through mud and snow or driving up or down

steep grades. This range provides the vehicle with maximum driving

power and maximum engine braking power.

9

RANGE SELECTION — AT 500 SERIES AND AT 1500 SERIES

WITHOUT A SECOND NEUTRAL (PARK)

; MT 640, MT(B) 643,

MT 643R, MT(B) 644, MT 647; HT 740, HT 747

R

Use this to back the vehicle. Completely stop the vehicle before shifting

from a forward range to

R

(Reverse) or from

R

(Reverse) to a forward

range. The reverse warning signal is activated when the shift selector is in

this position. Reverse has only one range. Reverse operation also

provides the greatest tractive advantage.

N

Use this position when you start the engine. If the engine starts in any

other position, the neutral start switch is malfunctioning. Neutral position

is also used during stationary operation of the power takeoff (if your

vehicle is equipped with a PTO).

D

The transmission will initially attain 1st range and, as vehicle speed

increases, the transmission will upshift to 2nd range, 3rd range, and 4th

range automatically. As the vehicle slows down, the transmission will

downshift to the correct range automatically.

WARNING: If you leave the vehicle and the engine is running, the

vehicle can move suddenly and you or others could be injured. If you

must leave the engine running, do not leave the vehicle until you:

• Put the transmission in N (Neutral)...and

• Apply the parking brake and emergency brakes and make sure they are

properly engaged...and

• Chock the wheels and take any other steps necessary to keep the

vehicle from moving.

WARNING: If you let the vehicle coast in N (Neutral), there is no

engine braking and you could lose control. Coasting can also cause

severe transmission damage. To help avoid injury and property damage,

do not allow the vehicle to coast in N (Neutral).

WARNING: If you just downshift or just use service brakes when going

downhill, you can lose control and cause injury and property damage. To

help avoid loss of control, use a combination of downshifting, braking,

and other retarding devices. Downshifting to a lower transmission range

increases engine braking and helps you to maintain control. The

transmission has a feature to prevent automatic upshifting above the

lower range selected. However, during downhill operation, if engine

governed speed is exceeded in the lower range, the transmission may

upshift to the next higher range. This will reduce braking and could

cause a loss of control. Apply the vehicle brakes or other retarding

device to prevent exceeding engine governed speed in the lower range

selected.

10

RANGE SELECTION — AT 500 SERIES AND AT 1500 SERIES

WITHOUT A SECOND NEUTRAL (PARK)

; MT 640, MT(B) 643,

MT 643R, MT(B) 644, MT 647; HT 740, HT 747

(cont’d)

3

2

Occasionally, the road, load, or traffic conditions will make it desirable to

restrict the automatic shifting to a lower range. (When conditions

improve, return the selector to the normal

D

(Drive) position.) These

positions also provide greater engine braking for going down grades (the

lower the range, the greater the braking effect).

1

Use this range when pulling through mud and snow or driving up or down

steep grades. This range provides the vehicle with maximum driving

power and maximum engine braking power.

11

RANGE SELECTION — MT 650; MT(B) 653DR

R

Use this to back the vehicle. Completely stop the vehicle before shifting

from a forward range to

R

(Reverse) or from

R

(Reverse) to a forward

range. The reverse warning signal is activated when the shift selector is in

this position. Reverse has only one range.

N

Use this position when you start the engine. If the engine starts in any

other position, the neutral start switch is malfunctioning. Neutral position

is also used during stationary operation of the power takeoff (if your

vehicle is equipped with a PTO).

2–5

D

The transmission will initially attain 2nd range and, as vehicle speed

increases, the transmission will upshift to 3rd range, 4th range, and 5th

range automatically. As the vehicle slows down, the transmission will

downshift to the correct range automatically.

2–4

Occasionally, the road, load, or traffic conditions will make it desirable to

restrict the automatic shifting to a lower range. (When conditions

improve, return the selector to the normal

D

(Drive) position.)

WARNING: If you leave the vehicle and the engine is running, the

vehicle can move suddenly and you or others could be injured. If you

must leave the engine running, do not leave the vehicle until you:

• Put the transmission in N (Neutral)...and

• Apply the parking brake and emergency brakes and make sure they are

properly engaged...and

• Chock the wheels and take any other steps necessary to keep the

vehicle from moving.

WARNING: If you let the vehicle coast in N (Neutral), there is no

engine braking and you could lose control. Coasting can also cause

severe transmission damage. To help avoid injury and property damage,

do not allow the vehicle to coast in N (Neutral).

WARNING: If you just downshift or just use service brakes when going

downhill, you can lose control and cause injury and property damage. To

help avoid loss of control, use a combination of downshifting, braking,

and other retarding devices. Downshifting to a lower transmission range

increases engine braking and helps you to maintain control. The

transmission has a feature to prevent automatic upshifting above the

lower range selected. However, during downhill operation, if engine

governed speed is exceeded in the lower range, the transmission may

upshift to the next higher range. This will reduce braking and could

cause a loss of control. Apply the vehicle brakes or other retarding

device to prevent exceeding engine governed speed in the lower range

selected.

12

RANGE SELECTION — MT 650; MT(B) 653DR

(cont’d)

2

2–3

Use this position for vehicle speed control up or down steep grades or for

other undesirable driving conditions.

1

This is the creeper range — select this for off-highway operation. Use the

creeper for pulling through mud or snow. This range provides the greatest

tractive advantage. It is not recommended that full-power 1–2 or 2–1

shifts be made.

13

RANGE SELECTION — HT 750CR, HT 754CR, MT(B) 654CR

R

Use this to back the vehicle. Completely stop the vehicle before shifting

from a forward range to

R

(Reverse) or from

R

(Reverse) to a forward

range. The reverse warning signal is activated when the shift selector is in

this position. Reverse operation provides the greatest tractive advantage.

Reverse has only one range.

N

Use this position when you start the engine. If the engine starts in any

other position, the neutral start switch is malfunctioning. Neutral position

is also used during stationary operation of the power takeoff (if your

vehicle is equipped with a PTO).

D

The transmission will initially attain 1st range and, as vehicle speed

increases, the transmission will upshift to 2nd range, 3rd range, 4th range,

and 5th range automatically. As the vehicle slows down, the transmission

will downshift to the correct range automatically.

WARNING: If you leave the vehicle and the engine is running, the

vehicle can move suddenly and you or others could be injured. If you

must leave the engine running, do not leave the vehicle until you:

• Put the transmission in N (Neutral)...and

• Apply the parking brake and emergency brakes and make sure they are

properly engaged...and

• Chock the wheels and take any other steps necessary to keep the

vehicle from moving.

WARNING: If you let the vehicle coast in N (Neutral), there is no

engine braking and you could lose control. Coasting can also cause

severe transmission damage. To help avoid injury and property damage,

do not allow the vehicle to coast in N (Neutral).

WARNING: If you just downshift or just use service brakes when going

downhill, you can lose control and cause injury and property damage. To

help avoid loss of control, use a combination of downshifting, braking,

and other retarding devices. Downshifting to a lower transmission range

increases engine braking and helps you to maintain control. The

transmission has a feature to prevent automatic upshifting above the

lower range selected. However, during downhill operation, if engine

governed speed is exceeded in the lower range, the transmission may

upshift to the next higher range. This will reduce braking and could

cause a loss of control. Apply the vehicle brakes or other retarding

device to prevent exceeding engine governed speed in the lower range

selected.

14

RANGE SELECTION — HT 750CR, HT 754CR, MT(B) 654CR

(cont’d)

4

3

2

Occasionally, the road, load, or traffic conditions will make it desirable to

restrict the automatic shifting to a lower range. (When conditions

improve, return the selector to the normal

D

(Drive) position.) The

positions also provide a greater engine braking for going down grades

(the lower the range, the greater the braking effect).

1

Use this range when pulling through mud and snow or driving up or down

steep grades. This range provides the vehicle with maximum driving

power and maximum engine braking power.

15

RANGE SELECTION — HT 750DR, HT 750DR DB

R

Use this to back the vehicle. Completely stop the vehicle before shifting

from a forward range to

R

(Reverse) or from

R

(Reverse) to a forward

range. The reverse warning signal is activated when the shift selector is in

this position. Reverse operation provides the greatest tractive advantage.

Reverse has only one range.

N

Use this position when you start the engine. If the engine starts in any

other position, the neutral start switch is malfunctioning. Neutral position

is also used during stationary operation of the power takeoff (if your

vehicle is equipped with a PTO).

2–5

The transmission will initially attain 2nd range and, as vehicle speed

increases, the transmission will upshift to 3rd range, 4th range, and 5th

range automatically. As the vehicle slows down, the transmission will

downshift to the correct range automatically.

2–4

2–3

Occasionally, the road, load, or traffic conditions will make it desirable to

restrict the automatic shifting to a lower range. (When conditions

improve, return the selector to the normal

D

(Drive) position.) The

positions also provide a greater engine braking for going down grades

(the lower the range, the greater the braking affect).

WARNING: If you leave the vehicle and the engine is running, the

vehicle can move suddenly and you or others could be injured. If you

must leave the engine running, do not leave the vehicle until you:

• Put the transmission in N (Neutral)...and

• Apply the parking brake and emergency brakes and make sure they are

properly engaged...and

• Chock the wheels and take any other steps necessary to keep the

vehicle from moving.

WARNING: If you let the vehicle coast in N (Neutral), there is no

engine braking and you could lose control. Coasting can also cause

severe transmission damage. To help avoid injury and property damage,

do not allow the vehicle to coast in N (Neutral).

WARNING: If you just downshift or just use service brakes when going

downhill, you can lose control and cause injury and property damage. To

help avoid loss of control, use a combination of downshifting, braking,

and other retarding devices. Downshifting to a lower transmission range

increases engine braking and helps you to maintain control. The

transmission has a feature to prevent automatic upshifting above the

lower range selected. However, during downhill operation, if engine

governed speed is exceeded in the lower range, the transmission may

upshift to the next higher range. This will reduce braking and could

cause a loss of control. Apply the vehicle brakes or other retarding

device to prevent exceeding engine governed speed in the lower range

selected.

16

RANGE SELECTION — HT 750DR, HT 750DR DB (cont’d)

2Use this position for vehicle speed control up or down steep grades or for

other undesirable road conditions.

1This is the creeper range — select this for off-highway operation. Use the

creeper for pulling through mud or snow. This range provides the greatest

tractive advantage. It is not recommended that 1–2 or 2–1 shifts be made

while the vehicle is moving.

17

THROTTLE CONTROL

The position of the throttle influences the automatic shifting. At wide open throttle, the

transmission will upshift automatically near the governed speed of the engine. At part

throttle, shifts will occur at a lower engine speed. When modulated lockup is

provided, closed-throttle operation delays the release of the lockup clutch to provide

additional engine braking at lower vehicle speeds.

DOWNSHIFT INHIBIT FEATURE

The transmission hydraulic system will inhibit a shift into any range at a speed that

will cause engine overspeed. Any lower, forward range may be selected at any time,

but the actual engagement will not occur until road speed is reduced; downshifting is

progressive as road speed decreases. The inhibit effect will cause downshifts to occur

at slightly higher speeds than normal automatic downshifts.

OPERATING IN COLD WEATHER

Refer to Table 2 on Page 31 for the minimum fluid temperatures at which the

transmission may be safely operated in a forward or reverse range. When ambient

temperature is below the minimum fluid temperature limit and the transmission is

cold, preheat is required. If auxiliary heating equipment is not available, run the

equipment or vehicle with the transmission in neutral for a minimum of 20 minutes

before attempting range operation.

CAUTION: Never shift from N (Neutral) to D (Drive) or

N (Neutral) to R (Reverse) at engine speeds above idle. The vehicle

will lurch forward or rearward and the transmission can be damaged.

CAUTION: Disregarding minimum fluid temperature limits can

result in transmission malfunction or reduced transmission life.

DRIVING TIPS

18

USING THE ENGINE FOR DOWNHILL BRAKING TO SLOW

THE VEHICLE OR EQUIPMENT

To use the engine as a braking force, select the next lower range. If the vehicle is

exceeding the maximum speed for the lower range, use the service brakes and/or

hydraulic retarder to slow the vehicle so that the lower range is obtained.

USING THE HYDRAULIC RETARDER

WARNING: The transmission incorporates a hold feature to pro-

hibit upshifting above the range selected during normal driving. For

downhill operation, select a lower transmission range. However, if

engine governed speed is exceeded in the held range, the transmis-

sion may upshift to the next higher range and damaging engine

overspeed is a possibility. Use the vehicle brakes or retarder to pre-

vent exceeding engine governed speed in the held range.

NOTE: Transmissions that do not have a lockup clutch (AT 540,

AT 542, AT 545) provide less engine braking than units which have a

lockup clutch. Downhill speed control for non-lockup units without a

retarder must rely on the service brakes.

WARNING: Do not use the retarder during inclement weather or

when road surfaces are slippery. De-energize the retarder at the

master control switch.

CAUTION: Observe the following cautions when driving a vehicle

equipped with an input or output retarder:

• APPLY AND OPERATE THE RETARDER WITH ENGINE AT

CLOSED THROTTLE ONLY.

• OBSERVE TRANSMISSION AND ENGINE TEMPERATURE

LIMITS AT ALL TIMES. Select the lowest possible

transmission range to increase the cooling system capacity and

total retardation available.

• OBSERVE THE RETARDER “ALERT LIGHT” to ensure that

the vehicle control system is functioning properly.

• DO NOT OPERATE THE INPUT OR OUTPUT RETARDER

SIMULTANEOUSLY WITH AN ENGINE EXHAUST BRAKE.

Extreme torque loads can be produced in the range section,

damaging the transmission.

• In the event of OVERHEATING, DECREASE USE OF THE

HYDRAULIC RETARDER; USE THE SERVICE BRAKES.

19

Hydraulic retarders are available on some models of the AT 500, MT 600, and HT 700

Series transmissions. The AT 500 retarder and the MT 643R input retarder are located

between the torque converter and the transmission gearing. The MT 600 output

retarder is installed on the rear of the transmission in place of the output housing. The

HT 700 retarder is installed between the torque converter and the transmission

gearing. The function of the retarder is to provide auxiliary retardation.

The AT 500 Series retarder is available on models without lockup or PTO provision.

The MT 643R retarder is available on models with lockup but without PTO provision.

The retarder is an integral part of the transmission which slows the vehicle by

applying a hydraulic braking force. Retardation and cooling are greatest at high input

(engine) speeds. Maintain high input speed by preselecting a lower range. The

external retarder controls (OEM-furnished) consist of a master switch and typical

options shown in Table 1. External retarder controls apply the retarder at the

50 percent or at the 100 percent level. External controls are also required to

automatically turn off the retarder in first range or when the vehicle anti-lock brake

system is activated. External controls also provide a signal to the modulator control.

The signal causes downshifts to occur at a higher speed when the retarder is operating

than would normally occur during closed throttle operation.

The MT 600 Series output retarder is mounted on the rear of the transmission as an

integral part of the transmission and provides your vehicle with an auxiliary

retardation system to slow the vehicle. The unit combines hydraulic and friction clutch

retardation capabilities. In many applications, the retarder is applied in conjunction

with the service brakes.

Table 1. Typical AT/MT Input Retarder Controls

Type Description Amount Of Application

Manual Manual 3-Position Switch 0%, 50%, Or 100%

Automatic 12V or 24V Signal When Closed Throttle Is Sensed 50% Or 100%

12V or 24V Signal When Brake Pedal Is Applied 50% Or 100%

Combination Manual 2-Position Switch and Closed Throttle

Sensor 50% From One Device,

100% From The Second

Device

Manual 2-Position Switch And Brake Pedal Apply 50% From Switch,

100% From Brake Pedal

Closed Throttle Sensor Plus Brake Apply Sensor 50% From Closed Throttle,

100% When Brake Applied

20

The HT 700 Series retarder, located between the torque converter and the transmission

gearing, provides hydraulic retardation capabilities to slow the vehicle. Maximum

retarder effect in this series occurs at high input speed. Selecting a lower hold range

position when using this type retarder is recommended for maximum effect.

Depending on the vehicle retarder apply system used, partial retarder application is

available when maximum application is not needed.

AUXILIARY TRANSMISSION

Select the desired auxiliary gear ratio while the vehicle is stopped. Do not shift the

auxiliary transmission while the vehicle is moving.

TWO-SPEED AXLE

The two-speed axle may be shifted from low to high or high to low while the

vehicle is moving without damaging the transmission. However, the axle or vehicle

manufacturer’s recommendations should be followed for shifting the axle. It is

recommended that axle shifts be made with the transmission in the highest range to

prevent a transmission range shift from coinciding with an axle shift.

TOWING OR PUSHING

PARKING BRAKE

On a vehicle with no P (Park) position on the transmission shift selector, always put

the selector in N (Neutral) and apply the parking brake (or emergency brake if the

vehicle is not equipped with a parking brake) to hold the vehicle when it is unattended.

CAUTION: Failure to disconnect the driveline or remove the axle

shafts before towing or pushing can cause serious transmission

damage.

The engine cannot be started by towing or pushing. Before towing

or pushing a vehicle, disconnect the driveline or lift the drive

wheels off the road. If the vehicle is a motor coach, remove the axle

shafts from the drive wheels. When the axle shafts are removed, be

sure to cover the wheel openings to prevent loss of lubricant and en-

try of dust and dirt. An auxiliary air supply will usually be required

to actuate the vehicle brake system.

21

DRIVING ON ICE OR SNOW

The ALLISON AUTOMATIC continuously provides proper balance between required

power and good traction. The driver can have better control of his vehicle because of

this smooth, constant flow of power through the drivetrain. When driving on ice or

snow, any acceleration or deceleration should be made gradually.

ROCKING OUT

If the vehicle is stuck in deep sand, snow, or mud, it may be possible to “rock” it out.

Shift to D (Drive) and apply steady, light throttle (never full throttle). When the

vehicle has rocked forward as far as it will go, apply and hold the vehicle service

brakes. Allow the engine to return to idle; then select R (Reverse). Apply a steady,

light throttle and allow the vehicle to rock in R (Reverse) as far as it will go. Again

apply and hold the service brakes and allow the engine to return to idle. This

procedure may be repeated in D (Drive) and R (Reverse) if each directional shift

continues to move the vehicle a greater distance. Never make neutral-to-range or

directional shift changes when the engine rpm is above idle.

TEMPERATURES

The transmission fluid temperature is indicated in some vehicles by a gauge which

usually indicates oil temperature to the cooler (converter out). In some vehicles the

only temperature indication is the engine coolant temperature indicator.

Some important transmission temperatures are shown in the following table.

WARNING: Do not use the retarder during inclement weather or

when road surfaces are slippery. De-energize the retarder at the

master control switch.

CAUTION: DO NOT make neutral-to-range or directional shift

changes when engine rpm is above idle. Failure to return to idle will

subject the transmission to excessive shock loads which could cause

clutch and/or shaft damage. Also, do not allow the transmission to

overheat while rocking out.

Sump Fluid, Minimum Continuous 100°F (40°C)

Sump Fluid, Typical Continuous 200°F (93°C)

Converter Out Fluid, Maximum 300°F (149°C)

Retarder Out Fluid, Maximum 330°F (165°C)

Sump Fluid, Maximum 250°F (121°C)

22

The transmission must never be operated above any of the maximum temperatures

shown in the table.

Extended operations at low vehicle speeds with the engine at full throttle or during

extended use of the hydraulic retarder can cause excessively high fluid temperatures in

the transmission. These temperatures may tend to overheat the engine cooling system

as well as cause possible transmission damage.

• If excessive temperature is indicated by the engine coolant temperature gauge,

stop the vehicle and determine the cause as soon as safely possible. If the

cooling system appears to be functioning properly, the transmission may be

overheated. Shift to N (Neutral) and accelerate the engine to 1200–1500 rpm.

If the transmission is the cause, this should reduce the engine coolant

temperature to operating level within a short time.

• If excessive temperature is indicated by the transmission fluid temperature

gauge, stop the vehicle as soon as safely possible and shift to N (Neutral).

Accelerate the engine to 1200–1500 rpm and allow the temperature to return

to normal (2 or 3 minutes) before resuming operation.

• If the transmission overheats during normal operation, check the fluid level in

the transmission. (Refer to the fluid check procedure found on Page 27 in the

Care and Maintenance section of this handbook.)

• If high temperature in either the engine or transmission persists, stop the

engine and have the overheating condition investigated by maintenance

personnel.

CAUTION: Never operate the engine for more than 30 seconds at

full throttle with the transmission in range and the output stalled.

Prolonged operation of this type will cause the transmission fluid

temperature to become excessively high and will result in severe

overheat damage to the transmission.

NOTE: When overheating occurs during retarder operation, do the

following.

• For output retarders, reduce retarder usage.

• For input retarders, reduce retarder usage and increase the

retarder’s cooling ability. For AT 500(R) or MT 643R input

retarders, overheating can be reduced by using 50 percent apply

instead of 100 percent.

23

ENGINE-DRIVEN PTO

Some models provide PTO mountings on the top and side of the torque converter

housing. The type of PTO installed will determine the operating procedures.

If the PTO driven gear is in constant mesh with the drive gear in the converter housing,

and a friction clutch is used to connect the PTO load, the PTO can be engaged or

disengaged at any time (except at engine speeds that exceed drive speed limits

imposed on the driven equipment). If the PTO is engaged by either a sliding gear or

dog clutch, the vehicle engine must be stopped to engage or disengage the PTO. Do

not exceed the drive speed limits of the driven equipment.

CONVERTER-DRIVEN PTO

A power takeoff may be mounted onto the mounting pad on the side of the

transmission. The PTO drive gear is turbine driven and thus provides infinitely

variable speeds. The power takeoff can be operated when the vehicle is either moving

or stopped. However, on some applications the PTO can be operated only when the

transmission is in neutral.

To operate the power takeoff, follow these instructions:

• Stop the vehicle, set the brakes, and idle the engine.

• Place the shift selector in a drive range.

CAUTION: Always allow the engine to return to idle speed before

shifting to a forward or reverse range after operating the PTO with

the transmission in neutral. Failure to return to idle will subject the

transmission to excessive shock loads which could cause clutch

and/or shaft damage.

POWER TAKEOFF

OPERATION

24

• Engage the PTO.

Typical PTO Drive Gear And Mounting Pad

• If the power takeoff will be operated while the vehicle is stopped, set the

parking brake, shift the transmission to N (Neutral), and depress the

accelerator as required. Disengage the PTO after returning the engine speed to

idle and stopping the PTO-driven equipment.

• If the power takeoff will be operated while the vehicle is moving, simply

select the desired range and depress the accelerator as required. However, the

speed of the power takeoff during this type of operation will be affected by the

ranges selected and the speed of the vehicle.

• To disengage the power takeoff, stop the vehicle, idle the engine, and set the

brake. Place the shift selector in a drive range, stop the PTO-driven

equipment, and disengage the power takeoff. Return the transmission shift

selector to N (Neutral).

CAUTION: Never engage the PTO by clashing the gear teeth. This

may damage the PTO unit and the PTO drive gear teeth. Stop clash-

ing by releasing the vehicle brakes and allowing the vehicle to

move slightly or by moving the shift selector from a drive range to

N (Neutral) and back to a drive range.

CAUTION: Do not exceed the speed limits imposed on the driven

equipment during operation of the PTO.

PTO DRIVE GEAR

PTO MOUNTING PAD

E00874.01

25

PERIODIC INSPECTIONS

The ALLISON AUTOMATIC requires minimum maintenance. Careful attention to

the fluid level, selector linkage, and throttle (modulator) linkage is most important.

For easier inspection, the transmission should be kept clean. Report any abnormal

condition to your maintenance personnel.

Inspect the transmission for the following.

• loose bolts (transmission and mounting components)

• transmission fluid leaks*

• shift linkage freely positioned by transmission detent

• for mechanical modulator valve actuators:

— full (and ease of) movement of mechanical modulator linkage

— vacuum or air line and modulator for leaks

• for electrical modulator valve actuators: proper connections, wire routing and

operation

• damaged or loose hydraulic lines

• damaged or loose electrical harnesses

• worn or frayed electrical connections

• driveline U-joints and slip fittings

• speedometer cable and fittings

• PTO linkage and driveline

Inspect the transmission fluid for the following.

• Check transmission and dropbox fluid levels regularly. Once consistent daily

hot level checks have been established and daily inspection shows no sign of

transmission leakage, less frequent checks could be made.

• Check the engine cooling system occasionally for evidence of transmission

fluid, which would indicate a faulty cooler.

* Transmission fluid leaks require immediate attention.

CARE AND

MAINTENANCE

26

PREVENT MAJOR PROBLEMS

Minor problems can be kept from becoming major problems if you notify

maintenance personnel when any of these conditions occur:

• Overheating

• Shifting feels odd

• Transmission leaks fluid

• Unusual transmission-related sounds (changes in sound level caused by

normal engine thermostatic fan cycling while climbing a long grade with a

heavy load have been mistaken for unusual transmission-related sounds).

IMPORTANCE OF PROPER FLUID LEVEL

Because the transmission fluid cools, lubricates, and transmits hydraulic power, it is

important that the proper fluid level be maintained at all times. If the fluid level is too

low, the converter and clutches will not receive an adequate supply of fluid. If the level

is too high, the fluid will aerate, the transmission will overheat, and fluid may be

expelled through the breather or dipstick tube.

Transmission Cross-Section Showing Internal Components

LOCKUP

CLUTCH

MODULATED LOCKUP VALVE

(OPTIONAL) CONVERTER-DRIVEN POWER

TAKEOFF DRIVE GEAR

MT 653DR

OIL FILTER

CONTROL VALVE BODY

GOVERNOR DRIVEN

GEAR

SPEEDOMETER

DRIVE GEAR

LOW CLUTCH

FIRST CLUTCH

SECOND

CLUTCH

THIRD CLUTCH

FOURTH

CLUTCH

FORWARD

CLUTCH

TORQUE

CONVERTER

V01960

27

TRANSMISSION FLUID CHECK PROCEDURE

Typical Dipstick Markings

WARNING: Take the following precautions so that unexpected, pos-

sible sudden vehicle movement is avoided. Whenever it becomes nec-

essary to leave the vehicle, even momentarily, while the engine is

running, place the transmission shift selector in N (Neutral) or P (Park),

set the parking brake and/or emergency brakes and chock the wheels.

CAUTION: Dirt and foreign matter must not be permitted to enter

the fluid system. It can cause valves to stick, cause undue wear of

transmission parts, or clog passages.

NOTE:

• Always check the transmission fluid level a minimum of two times.

Consistency is important in maintaining accuracy. If inconsistent

readings persist, check the transmission breather and the vent hole in

the dipstick fill tube to ensure they are clean and free of debris. The

vent hole is located on the underside of the fill tube just below the seal

of the dipstick cap.

• Transmissions equipped with a transfer gear housing (dropbox)

contain two separate hydraulic systems: the transmission system and

the dropbox system. Each system uses different transmission fluid and

must be checked independently.

V01961.01

REF

FILL COLD

RUN

BAND

OR HOT RUN

BAND

CHECK IN NEUTRAL AT

IDLE - USE DEXRON® FLUID

COLD RUN

BAND

HOT OVERFILL CHECK IN NEUTRAL AT

IDLE - USE DEXRON® FLUID

RECOMMENDED DIPSTICK MARKINGS

ALTERNATE DIPSTICK MARKINGS

28

Check the fluid level by the following procedures and record any abnormal fluid level,

milky appearance, or any trace of coolant in the fluid on your maintenance records.

Cold Check

• Park the vehicle on a level surface, set the parking brake and/or emergency

brakes, and chock the vehicle wheels.

• Run the engine at 1000–1500 rpm for 1 minute to purge air from the system.

Return engine to idle, then shift to D (Drive) and then to R (Reverse) to fill the

hydraulic circuits with fluid. Then shift to N (Neutral) or P (Park) and allow

the engine to idle (500–800 rpm). A cold check should be made when the

sump fluid temperature is 60–120˚F (16–49˚C). This temperature typically

occurs within the first ten minutes of operation during initial start-up.

• Clean around the end of the fill tube before removing the dipstick. Wipe the

dipstick clean and check the fluid level. If the fluid on the dipstick is within

the COLD RUN or REF FILL band, the level is satisfactory for operating the

transmission until the fluid is hot enough to perform a HOT RUN check. If the

fluid level is not within the COLD RUN or REF FILL band, add or drain fluid

as necessary to bring the level to the middle of the band.

• Perform a hot check at the first opportunity.

NOTE: The only purpose of the Cold Check is to determine if the

transmission has enough fluid to be safely operated until a Hot Check

can be made.

CAUTION: The fluid level rises as sump temperature increases.

DO NOT fill above the COLD RUN band if the transmission fluid

is below normal operating temperature.

NOTE: To ensure an accurate cold check, operate the transmission

until the sump fluid temperature is 60–120°F (16–49°C). This

temperature is usually reached within the first ten minutes of operation

from initial start-up.

29

Hot Check

• Shift to D (Drive) and then to R (Reverse) to fill the hydraulic circuits with

fluid.

• Park the vehicle on a level surface and shift to N (Neutral) or P (Park). Set the

parking brake and/or emergency brakes and chock the vehicle wheels. Allow

the engine to idle (500–800 rpm).

• After wiping the dipstick clean, check the fluid level. The safe operating range

is anywhere between the FULL and ADD lines, within the HOT RUN band,

or below the HOT OVERFULL mark and above the COLD RUN band.

• If the fluid level is outside of these parameters, raise or lower the fluid level to

bring it within the correct markings on the dipstick. Approximately one quart

(one liter) of fluid is required to raise the level from the bottom to the top of

the band.

DROPBOX FLUID CHECK PROCEDURE

• Bring the dropbox to operating temperature.

• Park the vehicle on level ground, set the parking brake, and turn off the

engine.

• If a level indicator (fill tube) is used, remove the fill tube plug and check the

fluid. Full capacity is indicated when the fluid is at the top of the fill tube.

Maintain a full capacity by adding the required amount of fluid.

• If a dipstick is used, wipe the dipstick clean. Insert the dipstick into the filler

tube, remove the dipstick and check the level. The safe level is any level

between the Full and Add marks on the dipstick. If the fluid level is on or

below the Add mark, add fluid as required.

NOTE: The fluid level rises as the temperature increases. To ensure an

accurate check, operate the transmission until the sump fluid

temperature is 160–200°F (71–93°C); converter-out temperature is

180–220°F (82–104°C). If a transmission temperature gauge is not

present, check fluid level when the engine water temperature gauge has

stabilized and the transmission has been operated under load for at least

one hour.

30

KEEPING FLUID CLEAN

It is absolutely necessary that the fluid put into the transmission be clean. Fluid must

be handled in clean containers, fillers, etc., to prevent foreign material from entering

the transmission. Lay dipstick in a clean place while filling the transmission.

RECOMMENDED AUTOMATIC TRANSMISSION FLUID AND

VISCOSITY GRADE — NON-MT 643R TRANSMISSIONS

Hydraulic fluids (oils) used in the transmission are important influences on

transmission performance, reliability, and durability.

• The following transmission fluid and viscosity grades are recommended.

— DEXRON®-III fluids for standard duty, on-highway applications

— Type C-4 fluids (Allison approved SAE 10W or SAE 30) for severe duty

and off-highway applications

— Type C-4 SAE 30 for all applications where the ambient temperature is

consistently above 95°F (35°C)

— Type C-4 SAE 30 for dropboxes

• Some DEXRON®-III fluids are also qualified as Type C-4 fluids. To ensure the

fluid is qualified for use in Allison transmissions, check for a DEXRON®-III or

C-4 fluid license, or approval numbers on the container, or consult the lubricant

manufacturer. Consult your Allison Transmission dealer or distributor before

using other fluid types; fluid types such as Type F, and universal farm fluids

may or may not be properly qualified for use in your Allison transmission.

• When choosing the optimum viscosity grade of fluid to use, duty cycle,

preheat capabilities, and/or geographical location must be taken into

consideration. Table 2 lists the minimum fluid temperatures at which the

CAUTION: Do not use containers or fillers for transmission fluid

that have been used to handle any antifreeze or engine coolant solu-

tion. Antifreeze and coolant solutions contain ethylene glycol

which, if introduced into the transmission, can cause the clutch

plates to fail.

CAUTION: Disregarding minimum fluid temperature limits can re-

sult in transmission malfunction or reduced transmission life.

31

transmission may be safely operated in a forward or reverse range.

Operation at ambient temperatures lower than those shown will require

preheating with auxiliary heating equipment or by running the vehicle with

the transmission in N (Neutral) for a minimum of 20 minutes before

attempting range operation.

RECOMMENDED AUTOMATIC TRANSMISSION FLUID AND

VISCOSITY GRADE — MT 643R TRANSMISSIONS

• Due to the added heat load from the input retarder, MT 643R transmissions

require special fluid considerations. The approved fluids list is more restrictive

than for non-retarder MT 643R transmissions. Also, the fluid change intervals

are shorter than for non-retarder MT 643R transmissions.

• Only high quality, heavy duty diesel engine oils that are approved Allison C-4

fluids with a viscosity of either SAE 30 or SAE 15W-40 are recommended for

use in MT 643R transmissions. For specific name brands, contact the local

Allison Transmission Regional Office.

• Refer to Table 2 for minimum fluid temperatures at which the transmission

may be safely operated with various fluids. Operation at ambient tempera-

tures lower than those shown will require preheating with auxiliary heating

equipment or by running the vehicle with the transmission in N (Neutral)

for a minimum of 20 minutes before attempting range operation.

CAUTION: Disregarding minimum fluid temperature limits can re-

sult in transmission malfunction or reduced transmission life.

Table 2. Operating Temperature Requirements for Transmission Fluid

Viscosity Grade Ambient Temperature Below Which Preheat

Is Required

Fahrenheit Celsius

SAE 0W-20 –31 –35

DEXRON®-III –22 –30

SAE 10W –4 –20

SAE 15W-40 5 –15

SAE 30 32 0

SAE 40 50 10

32

FLUID AND FILTER CHANGE INTERVALS

Fluid and filter change frequencies are determined as follows.

• Table 3 is a general guide. The fluid must be changed whenever there is

evidence of dirt or high temperature indicated by discoloration or strong odor.

More frequent changes may be required when operations are subject to high

levels of contamination or overheating.

• Fluid change intervals can be optimized by monitoring fluid oxidation

according to the tests and limits in the Fluid Contamination section of this

manual.

Table 3. Fluid and Filter Change Intervals

Transmission

Application Fluid Change Internal Sump

Filter Governor

Filter External

Auxiliary Filter**

AT 500

and 1500 Series

(On-Highway)

(Light-Duty)

(School Bus,

Motorhome, and

One-Way Rental)

Paper Filter:

25,000 miles

(40 000 km)

or 12 months*

Brass Filter:

50,000 miles

(80 000 km)

or 24 months*

Paper Filter in Shallow

Pan (4.0 in.) or

Deep Pan (5.3 in.):

25,000 miles (40 000 km)

or 12 months*

Brass Screen Filter in

Shallow Pan (4.0 in.) or

Deep Pan (5.3 in.):

50,000 miles (80 000 km)

with no time limit

At overhaul After first 5000 miles

(8000 km) and at

25,000 miles

(40 000 km) or

12 months, thereafter

AT 500,

AT 500R,

and 1500 Series

(On-Highway)

(Heavy-Duty)

25,000 miles

(40 000 km)

or 12 months*

Paper Filter in Shallow

Pan (4.0 in.) or Deep Pan

(5.3 in.): 25,000 miles

(40 000 km) or

12 months*

Brass Screen Filter in

Shallow Pan (4.0 in.)

or Deep Pan (5.3 in.):

50,000 miles (80 000 km)

with no time limit

At overhaul After first 5000 miles

(8000 km) and at

normal fluid change

intervals, thereafter

AT 500

and 1500 Series

(Off-Highway)

1000 hours

max

or 12 months*

Paper Filter in Shallow

Pan (4.0 in.), or Deep Pan

(5.3 in.): at each oil

change interval

Brass Screen Filter in

Shallow Pan (4.0 in.) or

Deep Pan (5.3 in.): at each

oil change interval*

At overhaul After first 500 hours

and at normal oil

change intervals,

thereafter

MT 600 Series

(On-Highway,

Non-MT 643R)

25,000 miles

(40 000 km)

or 12 months*

Paper Filter:

25,000 miles (40 000 km)

or 12 months*

Stainless Steel Screen:

At overhaul

25,000 miles

(40 000 km)

or 12 months*

After first 5000 miles

(8000 km) and at

normal oil change

intervals, thereafter

(cont’d on next page)

33

FLUID CONTAMINATION

Examine at Fluid Change

At each fluid change, examine the fluid which is drained for evidence of dirt or engine

coolant (water). A normal amount of condensation will emulsify in the fluid during

operation of the transmission. However, if there is evidence of coolant, check the

cooler (heat exchanger) for leakage between the cooler and fluid areas. Fluid in the

coolant side of the cooler (heat exchanger) is another sign of leakage. This, however,

may indicate leakage from the engine oil system.

Metal Particles

Metal particles in the fluid (except for the minute particles normally trapped in the

filter) indicate damage has occurred in the transmission. When these particles are

Transmission

Application Fluid Change Internal Sump

Filter Governor

Filter External

Auxiliary Filter**

MT 643R After first

5000 miles

(8000 km) then

at 20,000 miles

(32 000 km) or

12 months*

Paper Filter:

At every other fluid

change

Stainless Steel Screen:

At overhaul

20,000 miles

(32 000 km)

or 12 months*

After first 5000 miles

(8000 km) then at

each fluid change

thereafter*

MT 600 Series

(Off-Highway)

1000 hours

maximum

or 12 months*

Paper Filter:

1000 hours maximum or

12 months*

Stainless Steel Screen:

At overhaul

1000 hours

maximum or

12 months*

After first 500 hours

and at normal oil

change intervals,

thereafter

HT 700 Series

(All Applications)

50,000 miles

(80 000 km) or

12 months or

1200 hours*

At overhaul At overhaul After first 5000 miles

(8000 km) and at each

25,000 miles

(40 000 km) or

6 months or

600 hours, thereafter*

* Whichever occurs first.

** An Allison high-efficiency filter may be used until the Change Filter light indicates it is

contaminated or until it has been in use for 3 years, whichever occurs first. No mileage restrictions

apply.

CAUTION: Whenever excessive metal contamination has oc-

curred, replacement of the cooler and replacement of all bearings

within the transmission is recommended.

Table 3. Fluid and Filter Change Intervals (cont’d)

34

found in the sump or on the magnetic plate in the bottom of the pan (if present), the

transmission must be disassembled and closely inspected to find the source. Metal

contamination requires complete disassembly of the transmission and cleaning of all

internal and external circuits, cooler, and all other areas where the particles could

lodge. (Refer to Auxiliary Filter.)

Coolant Leakage

If engine coolant leaks into the transmission hydraulic system, take immediate action

to prevent malfunction and possible serious damage. Completely disassemble, inspect,

and clean the transmission. Remove all traces of the coolant and varnish deposits

resulting from coolant contamination. Replace friction clutch plates contaminated

with ethylene glycol.

Fluid Analysis

Transmission protection and fluid change intervals can be optimized by transmission

fluid analysis. Consult your local telephone directory for fluid analysis firms. Use one

fluid analysis firm as results from various firms cannot be accurately compared. Refer

to the Technicians’ Guide for Automatic Transmission Fluid (SA2055) for additional

information.

To optimize transmission protection, the following is the minimum series of tests

required to properly monitor the condition of the transmission and transmission

fluid/filter system.

• Wear Metals (ppm): Fe, Cu, Pb, Al

• Additive and Contaminant Metals (ppm): Ba, B, Ca, Mg, P, Si, Na, Zn

• Non-metal Contaminants: Fuel (% vol), Soot (% wt), Water (% vol)

• Viscosity (cSt) at 40˚C (ASTM D445)

• Viscosity (cSt) at 100˚C (ASTM D445)

• TAN (Total Acid Number) (ASTM D664)

• Particle Counts (particles/ml) at >5, >10, >20, >30, and >40 microns

ppm = parts per million cSt = centiStokes ml = milliliter

To optimize fluid change intervals, monitor fluid oxidation per the tests and limits

shown in Table 4. A fluid is considered suitable for use if it meets all four limits listed

in the table, regardless of color or odor. If one of the limits is exceeded, however, the

35

fluid in the subject transmission should be sampled again immediately to verify the

exceeded limit. If verified, the fluid should be changed regardless of time or mileage.

AUXILIARY FILTER

If a condition occurs that introduces debris into the transmission hydraulic system, a

complete cleanup of the cooler and lines is recommended.

Repeated cleaning and flushing may not remove all debris. For models with a retarder,

replace the main cooler. For models without a retarder, install an auxiliary filter in the

cooler-out line (between the cooler and transmission) if such a filter does not already

exist. This filter has already been included in many recently built vehicles. This

recommendation applies whether the transmission is overhauled or replaced by a new

or rebuilt unit.

If any doubt exists about the cleanup of the cooler, replace the cooler.

Consult your nearest Allison Transmission dealer/distributor or the chassis OEM for

detailed filter information and availability.

Table 4. Fluid Oxidation Measurement Limits

Condition Limit

Viscosity ± 25% Change From New Fluid

Carbonyl Absorbance

Total Acid Number (TAN)

Solids

+ 30* Change From New Fluid

+ 3.0** Change From New Fluid

2% By Volume Maximum

* Carbonyl absorbance units/cm

** mg of KOH required to neutralize a g of fluid

CAUTION: DO NOT install an auxiliary filter in the AT 500R or

MT 643R primary cooler circuit. This reduces retarder effective-

ness. An auxiliary filter in the secondary cooler circuit is sufficient.

36

OWNER ASSISTANCE

The satisfaction and goodwill of the owners of Allison transmissions are of primary

concern to Allison Transmission Division (ATD), its distributors, and their dealers.

As an owner of an Allison transmission, you have service locations throughout the

world that are eager to meet your parts and service needs with:

• Expert service by trained personnel

• Emergency service 24 hours a day in many areas

• Complete parts support

• Sales teams to help determine your transmission requirements

• Product information and literature

Normally, any situation that arises in connection with the sale, operation, or service of

your transmission will be handled by the distributor or dealer in your area (check the

telephone directory for the Allison Transmission service outlet nearest you).

Reference the Sales and Service Directory (SA2229) for the current listing of Allison

Transmission authorized distributor and service dealers.

We recognize, however, that despite the best intentions of everyone concerned,

misunderstandings may occur. To further assure your complete satisfaction, we have

developed the following three-step procedure to be followed in the event a problem

has not been handled satisfactorily.

Step One — Discuss the problem with a member of management from the

distributorship or dealership. Frequently, complaints are the result of a breakdown

in communication and can quickly be resolved by a member of management. If you

have already discussed the problem with the Sales or Service Manager, contact the

General Manager. All ATD dealers are associated with an ATD distributor. If the

problem originates with a dealer, explain the matter to a management member of the

distributorship with whom the dealer has his service agreement. The dealer will

provide his ATD distributor’s name, address, and telephone number on request.

CUSTOMER SERVICE

37

Step Two — When it appears the problem cannot be resolved readily at the distributor

level without additional assistance, contact the Allison Transmission Regional

Office responsible for the local distributor. You will be assisted by a member of the

Regional Service Manager’s staff, depending on the nature of your problem.

For prompt assistance, please have the following information available.

• Name and location of authorized distributor or dealer

• Type and make of equipment

• Transmission model number, serial number, and assembly number (if

equipped with electronic controls, also provide the ECU assembly number)

• Transmission delivery date and accumulated miles and/or hours of operation

• Nature of problem

• Chronological summary of unit’s history

Step Three — If you contacted a regional office and you are still not satisfied, present

the entire matter to the Home Office by writing to the following address or

calling the phone number below:

Manager, Warranty Administration – PF9

Allison Transmission

P.O. Box 894

Indianapolis, IN 46206-0894

Phone: (317) 242-2052

The inclusion of all pertinent information will assist the Home Office in expediting the

matter. If an additional review by the Home Office of all the facts involved indicates

that some further action can be taken, the Regional Office will be advised.

When contacting the Regional or Home Office, please keep in mind that ultimately the

problem will likely be resolved at the distributorship or dealership utilizing their

facilities, equipment, and personnel. Therefore, it is suggested the above steps be

followed in sequence when experiencing a problem.

Your purchase of an Allison Transmission product is greatly appreciated, and it is our

sincere desire to assure complete satisfaction.

38

SERVICE LITERATURE

Additional service literature is available as shown in Table 5. This service literature

provides fully illustrated instructions for the operation, maintenance, service,

overhaul, and parts support of your transmission. To ensure that you get maximum

performance and service life from your unit, you may order publications from:

SGI, Inc.

Attn: Allison Literature Fulfillment Desk

8350 Allison Avenue

Indianapolis, IN 46268

TOLL FREE: 888-666-5799

INTERNATIONAL: 317-471-4995

Table 5. Service Literature

Transmission Series Mechanic’s

Tips Service

Manual Parts

Catalog Technician’s

Guide

AT 540,

AT 542(N)(R)(NFE),

AT 543,

AT 545(N)(R),

AT 1542P,

AT 1545P(N)

SA1321 SA1241 SA2126

SA1235

SA3048

SA1948

SA2055*

MT 640,

MT(B) 643, MT 643R

MT 650,

MT(B) 653

SA1357 SA1317 SA1316

SA3046 SA2009**

SA2055*

MT, MTB 644,

MT, MTB 647,

MT, MTB 654CR SA1357 SA1546 SA1551 SA2006◊

SA2009**

SA2055*

HT 740(D)(RS)(FS),

HT 747(D),

HT 750CRD,

HT 750DR (DB)(RS),

HT 750DRI,

HT 750DRD (DB),

HT 754CRD,

HT 754CR (RS)

SA1366 SA1270 SA1268

SA3032 SA2033

SA2055*

* Automatic Transmission Fluid

** Output Retarder Inspection/Analysis

◊MT 654CR only

39

ALLISON TRANSMISSION DISTRIBUTORS

EASTERN REGION

Atlantic Detroit Diesel-Allison, LLC

180 Route 17 South

Lodi, NJ 07644

201-489-5800

Penn Detroit Diesel-Allison, Inc.

8330 State Road

Philadelphia, PA 19136-2986

215-335-0500

Covington Detroit Diesel-Allison

8015 Piedmont Triad Parkway

Greensboro, NC 27409

336-292-9240

Western Branch Diesel, Inc.

3504 Shipwright Street

Portsmouth, VA 23703

757-484-6230

Johnson & Towers, Inc.

2021 Briggs Road

Mount Laurel, NJ 08054

856-234-6990

Williams Detroit Diesel-Allison

Southeast, Inc.

2849 Moreland Avenue, S.E.

Atlanta, GA 30315-0037

404-366-1070

New England Detroit Diesel-Allison, Inc.

90 Bay State Road

Wakefield, MA 01880-1095

781-246-1810

40

CENTRAL REGION

Caribe Detroit Diesel-Allison

Division of GT Corporation

Ceramic Ind. Park, Campo Rico Ave.,

Block C

Carolina, Puerto Rico 00982

787-750-5000

Inland Diesel, Inc.

13015 West Custer Avenue

Butler, WI 53007-0916

262-781-7100

Central Detroit Diesel-Allison, Inc.

9200 Liberty Drive

Liberty, MO 64068

816-781-8070

Interstate Detroit Diesel

2501 East 80th Street

Minneapolis, MN 55425

612-854-5511

Clarke Detroit Diesel-Allison, Inc.

3133 East Kemper Road

Cincinnati, OH 45241

513-771-2200

Inland Detroit Diesel-Allison, Inc.

210 Alexandra Way

Carol Stream, IL 60195

630-871-1111

Florida Detroit Diesel-Allison, Inc.

5105 Bowden Road

Jacksonville, FL 32216

904-737-7330

Williams Detroit Diesel-Allison

Midwest, Inc.

1176 Industrial Parkway, North

Brunswick, OH 44212-2342

330-225-7751

SOUTHWESTERN REGION

Detroit Diesel-Allison De Mexico S.A.

De C.V.

Av. Ejercito Nacional #843

Colonia Granada, Mexico D.F.

C.P. 11520

525-901-3057

United Engines, Inc.

5555 West Reno Avenue

Oklahoma City, OK 73127

405-947-3321

Stewart & Stevenson Power, Inc.

5840 Dahlia Street

Commerce City, CO 80022

303-287-7441

Stewart & Stevenson Services, Inc.

2707 North Loop West

Houston, TX 77008

713-868-7700

41

WESTERN REGION

Pacific Detroit Diesel-Allison Company

7215 South 228th Street

Kent, WA 98032

253-854-0505

Valley Detroit Diesel-Allison, Inc.

425 South Hacienda Boulevard

City of Industry, CA 91745-1123

626-333-1243

Sierra Detroit Diesel-Allison, Inc.

1755 Adams Avenue

San Leandro, CA 94577-1001

510-635-8991

Williams Detroit Diesel-Allison

Southwest, Inc.

2602 S. 19th Avenue

Phoenix, AZ 85009

602-257-0561

Smith Detroit Diesel-Allison, Inc.

250 West 3900 South

Salt Lake City, UT 84107

801-262-2631

CANADIAN REGION

Detroit Diesel-Allison

British Columbia Ltd.

9300 - 192nd Street

Surrey, British Columbia V4N 3R8

604-888-1211

Midwest Detroit Diesel-Allison Ltd.

1460 Waverley Street

Winnipeg, Manitoba R3T OP6

204-452-8244

Detroit Diesel-Allison Canada East

(Div. of Integrated Power Systems Corp.)

2997 Rue Watt

Ste. Foy, Quebec G1X 3W1

418-651-5371

Waterous Detroit Diesel-Allison (Div.

of Integrated Power Systems Corp)

10025 - 51 Avenue

Edmonton, Alberta T6E OA8

780-437-3550

Harper Detroit Diesel Ltd.

10 Diesel Drive

Toronto, Ontario M8W 2T8

416-259-3281

42

ALLISON TRANSMISSION REGIONAL OFFICES

EASTERN REGION

19 Oaklynn Drive

P. O. Box 400

Columbus, NJ 08022-0400

609-298-2541

WESTERN REGION

39465 Paseo Padre Parkway

Suite 2400

Fremont, CA 94538

510-498-5208

CENTRAL REGION

P. O. Box 894, Speed Code PF06

Indianapolis, IN 46206

317-242-2327

CANADIAN REGION

P. O. Box 5160, Station A

London, Ontario N6A 4N5

519-452-5256

SOUTHWESTERN REGION

Phone: 936-321-4248

Fax: 936-321-4278

OM1334EN 199907 Printed in U.S.A. 200005