Allison Transmission AT 542N, AT 542R, AT 543, AT 542NFE, AT 545 Operator's Manual
...
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, howev er, 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 T ransmission has not undertak en an y 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 w arning 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 adv antages for the driv er 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 Allisonequipped 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 conv erter, a
planetary gear train, and a hydraulic control system which supplies fluid under
pressure to apply the clutches and automatically shift ranges.
The torque conv erter 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 conv erter 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 conv erter 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 conv erter is continuously filled with fluid. The pump, dri ven 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 flo w 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 conv erter 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 conv erter 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 conv erter pump to the turbine and provides a direct dri v e from the
engine to the transmission. The lockup clutch automatically releases at lower v ehicle
speeds. When the lockup clutch is not engaged, dri ve from the engine is transmitted
hydraulically through the conv erter to the transmission gearing.
4
Because the conv erter lockup engagement and release are designed to fit the v ehicle’s
vocation, there are many v ariations 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 a vailable 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 closedthrottle 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 dri ver
who counts shifts should not confuse lockup with a range change. A little driving
experience with the Allison automatic will enable the driv er 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 ha ve
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 a vailable
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 rev erse w arning signal is acti v ated when the shift selector is in
this position. Reverse has only one range. Re v erse 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 the y 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. T o
help avoid loss of control, use a combination of downshifting, braking,
and other retarding devices. Do wnshifting to a lo wer 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. Ho wever, 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 pre v ent 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 dri ving up or do wn
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 rev erse 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 the y 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. T o
help avoid loss of control, use a combination of downshifting, braking,
and other retarding devices. Do wnshifting to a lo wer 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. Ho wever, 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 pre v ent 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 dri ving up or do wn
steep grades. This range provides the vehicle with maximum driving
power and maximum engine braking power.
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