Allison Transmission 3000, 4000 Operators Manual
MOTO RHOME SERIES
3000/4000
OPERATOR’S
MANUAL
Operator’s
Manual
2005 FEBRUARY
Rev. 1 2005 SEPTEMBER
OM3349EN
Allison Transmission
VOCATIONAL MODELS
Motorhome Series (MH) Transmissions
3000 and 4000 Product Families
WTEC III Controls and Allison 4
3000 MH
4000 MH
th
Generation Controls
Printed in USA
Copyright © 2005 General Motors Corporation
NOTES
2
TABLE OF CONTENTS
INTRODUCTION
KEEPINGTHATALLISONADVANTAGE ........................ 7
A BRIEF DESCRIPTION OF THE ALLISON MOTORHOME SERIES
TRANSMISSIONS ...................................... 12
ELECTRONIC CONTROL SYSTEM ........................... 12
TORQUE CONVERTER ................................... 13
PLANETARYGEARSANDCLUTCHES ........................ 14
COOLER CIRCUIT ...................................... 14
RETARDER...........................................15
SHIFT SELECTORS
DESCRIPTION OF AVAILABLE TYPES .........................16
INTRODUCTION ....................................... 17
LEVER SHIFT SELECTOR ................................. 18
PUSHBUTTON SHIFT SELECTOR ............................20
RANGE SELECTION ..................................... 21
DRIVING TIPS
CHECKTRANSLIGHT ................................... 26
DIAGNOSTIC CODES .................................... 27
ACCELERATOR CONTROL ................................ 27
DOWNSHIFT AND DIRECTION CHANGE INHIBITOR FEATURE ....... 27
USINGTHEENGINETOSLOWTHEVEHICLE ................... 29
USING THE HYDRAULIC RETARDER ......................... 29
ADAPTING SHIFTS ..................................... 32
RANGE PRESELECTION .................................. 34
COLDWEATHERSTARTS ................................. 34
DRIVING ON SNOW OR ICE ............................... 35
ROCKINGOUT ........................................ 36
HIGHFLUIDTEMPERATURE .............................. 36
PARKINGBRAKE ...................................... 37
TOWING OR PUSHING ...................................38
PRIMARY/SECONDARY SHIFT SCHEDULES .................... 38
CRUISECONTROLOPERATION ............................. 38
TURNINGOFFTHEVEHICLE .............................. 39
POWER TAKEOFF OPERATION
ENGINE-DRIVENPOWERTAKEOFF(PTO) ..................... 40
3
CARE AND MAINTENANCE
PERIODIC INSPECTIONS ................................. 41
PREVENT MAJOR PROBLEMS ..............................41
IMPORTANCE OF PROPER FLUID LEVEL ...................... 42
FLUID LEVEL CHECK USING PUSHBUTTON OR LEVER SHIFT
SELECTOR ...........................................43
MANUAL FLUID CHECK PROCEDURE ....................... 47
COLDCHECK ......................................... 49
HOTCHECK .......................................... 50
RECOMMENDED AUTOMATIC TRANSMISSION FLUID AND VISCOSITY
GRADE ............................................. 50
KEEPINGFLUIDCLEAN ..................................51
FLUID AND INTERNAL FILTER CHANGE INTERVAL
RECOMMENDATIONS ................................... 52
TRANSMISSION FLUID CONTAMINATION ..................... 56
TRANSMISSION FLUID AND FILTER CHANGE PROCEDURE ......... 57
DIAGNOSTICS
INTRODUCTION ....................................... 60
DIAGNOSTIC CODES .................................... 60
DIAGNOSTIC CODE DISPLAY PROCEDURE .....................63
DIAGNOSTIC CODE LISTINGS AND PROCEDURES
(WTECIIICONTROLS) ................................... 65
DIAGNOSTIC CODE LISTINGS AND PROCEDURES (ALLISON 4
GENERATIONCONTROLS) ................................ 73
th
ABBREVIATIONS AND DEFINITIONS
ABBREVIATIONS AND DEFINITIONS ......................... 84
CUSTOMER SERVICE
OWNER ASSISTANCE ................................... 86
SERVICELITERATURE ...................................88
ALLISON TRANSMISSION DISTRIBUTORS ..................... 90
ALLISON TRANSMISSION REGIONAL OFFICES .................. 92
4
TRADEMARK USAGE
The following trademarks are the property of the companies indicated:
• Allison DOC™ is a trademark of General Motors Corporation.
• DEXRON
• TranSynd™ is a trademark of Castrol Ltd.
®
is a registered trademark of the General Motors Corporation.
5
WARNINGS, CAUTIONS, NOTES
IT IS YOUR RESPONSIBILITY to be completely familiar with the warnings
and cautions described in this manual. 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. The vehicle manufacturer is responsible for providing information related to
the operation of vehicle systems (including appropriate warnings, cautions, and
notes). 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 OR THE VEHICLE MANUFACTURER 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 (or the
vehicle manufacturer) and described in this manual 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.
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.
NOTE: A note is used when an operating procedure, practice, etc., is
essential to highlight.
6
INTRODUCTION
KEEPING THAT ALLISON ADVANTAGE
Allison Motorhome Series (MH) transmissions provide many advantages for the
driver who must “stop and go” or change speeds frequently. Driving is easier,
safer, and more efficient.
The Motorhome Series transmissions are rugged and designed to provide long,
trouble-free service. This manual will help you gain maximum benefits from your
ALLISON-equipped vehicle.
7
BREATHER
ASSEMBLY PADS
OUTPUT
SPEED
SENSOR
COOLER PORTS
NOTE: Inch Series Threads
TORQUE CONVERTER
WITH LOCKUP CLUTCH
AND TORSIONAL DAMPER
BREATHER
INPUT
SPEED
SENSOR
FEEDTHROUGH
HARNESS
CONNECTOR
NAMEPLATE
MAIN-PRESSURE TAP
NOTE: Inch Series Threads
FEEDTHROUGH
HARNESS
CONNECTOR
ASSEMBLY
PADS
(BOTH SIDES)
FILL TUBE
AND DIPSTICK
(Available on
both sides)
MAIN-PRESSURE TAP
NOTE: Inch Series Threads
Figure 1. Typical 3000 MH Series Transmission
(WTEC III Controls)
8
V06341.02.00
BREATHER
ASSEMBLY PADS
OUTPUT
SPEED
SENSOR
COOLER PORTS
NOTE: Inch Series Threads
FEEDTHROUGH
HARNESS CONNECTOR
TORQUE CONVERTER
WITH LOCKUP CLUTCH
AND TORSIONAL DAMPER
BREATHER
INPUT
SPEED
SENSOR
FILL TUBE
AND DIPSTICK
(Available on
both sides)
NAMEPLATE
MAIN-PRESSURE TAP
NOTE: Inch Series Threads
ASSEMBLY
PADS
(BOTH SIDES)
FILL TUBE
AND DIPSTICK
(Available on
both sides)
MAIN-PRESSURE TAP
NOTE: Inch Series Threads
Figure 2. Typical 3000 MH Series Transmission
(Allison 4
th
Generation Controls)
9
V06341.03.01
FEEDTHROUGH
HARNESS
CONNECTOR
OUTPUT SPEED
SENSOR
COOLER PORTS
MOUNTING PAD
(BOTH SIDES)
BREATHER
MOUNTING
PAD
INPUT SPEED
SENSOR
TURBINE SPEED
SENSOR
FILL TUBE AND DIPSTICK
NAMEPLATE
BREATHER
MAIN-PRESSURE TAP
Figure 3. Typical 4000 MH Series Transmission
(WTEC III Controls)
10
FEEDTHROUGH
HARNESS
CONNECTOR
COOLER PORTS
V06342
OUTPUT SPEED
SENSOR
COOLER PORTS
FEEDTHROUGH
HARNESS CONNECTOR
MOUNTING PAD
(BOTH SIDES)
BREATHER
MOUNTING
PAD
INPUT SPEED
SENSOR
TURBINE SPEED
SENSOR
FILL TUBE AND DIPSTICK
NAMEPLATE
BREATHER
MAIN-PRESSURE TAP
Figure 4. Typical 4000 MH Series Transmission
(Allison 4
th
Generation Controls)
11
COOLER PORTS
V06342.01.00
A BRIEF DESCRIPTION OF THE ALLISON MOTORHOME SERIES TRANSMISSIONS
Included in the Allison On-Highway Transmission family are the Motorhome
Series transmissions. The transmissions described in this manual include:
th
• WTEC III Controls or Allison 4
Generation Controls
• A torque converter with lockup and torsion damper
• Three planetary gear sets
Motorhome Series transmissions may contain an integral retarder or a provision to
mount a Power Takeoff (PTO).
ELECTRONIC CONTROL SYSTEM
All Motorhome Series transmissions come standard with WTEC III Controls or
Allison 4
connected by OEM-furnished wiring harnesses. The five major components are:
The TCM/ECU receives information from the following:
The TCM/ECU processes information and then sends signals to actuate specific
solenoids located in the control valve module. These solenoids control both
oncoming and offgoing clutch pressures to provide closed-loop shift control by
matching input rpm during a shift to a desired profile programmed into the
TCM/ECU.
th
Generation Controls. These systems consist of five major components
• Transmission Control Module (TCM) or Electronic Control Unit (ECU)
• Three speed sensors
• Remote shift selector
• Control module (which contains solenoid valves, a pressure switch, and an
optional oil level sensor)
• Engine Electronic Control Module (ECM) or Engine Throttle Position
Sensor (TPS), if installed
• Throttle position sensor, if installed
• Speed sensors
• Pressure switch
• Shift selector
12
A feature of both Allison 4thGeneration Controls and WTEC III controls is
“autodetect.” Autodetect is active within the first several engine starts, depending
upon the component or sensor being detected. These engine start cycles begin
when the transmission is installed during vehicle manufacture. Autodetect searches
for the presence of the following transmission components or data inputs:
Transmission Components
Retarder Present, Not Present
Oil Level Sensor (OLS) Present, Not Present
Throttle Analog, J1587, J1939
Engine Coolant Temperature Analog, J1939, J1587
Seek help from the nearest Allison Transmission service outlet when any of the
above components are present, but are not responding properly.
Another feature of the Motorhome Series transmission is its ability to adapt or
“learn” as it operates. Each shift is measured electronically, stored, and used by
the TCM/ECU to adapt or “learn” the optimum control for future shifts.
NOTE: Allison 4thGeneration Controls and WTEC III Controls are
designed and manufactured to comply with all FCC and other guidelines
regarding radio frequency interference/electromagnetic interference
(RFI/EMI) for transportation electronics. Manufacturers, assemblers, and
installers of radio-telephone or other two-way communication radios
have the sole responsibility to correctly install and integrate those
devices into Allison Motorhome Series transmission-equipped vehicles
to customer satisfaction.
The TCM/ECU is programmed to provide the most suitable operating
characteristics for a specific application. This manual does not attempt to describe
all of the possible combinations. The information contained herein describes only
the operating characteristics most frequently requested by the vehicle
manufacturer.
TORQUE CONVERTER
The torque converter consists of the following four elements:
• Pump—input element driven directly by the engine
• Turbine—output element hydraulically driven by the pump
• Stator—reaction (torque multiplying) element
• Lockup Clutch—mechanically couples the pump and turbine when engaged;
controlled by TCM/ECU
13
When the pump turns faster than the turbine, the torque converter is multiplying
torque. When the turbine approaches the speed of the pump, the stator starts to
rotate with the pump and turbine. When this occurs, torque multiplication stops
and the torque converter functions as a fluid coupling.
The lockup clutch is located inside the torque converter and consists of the
following elements:
• Piston and backplate—driven by the engine
• Clutch plate/damper (located between the piston and the
backplate)—splined to the converter turbine
The lockup clutch/torsional damper is engaged and released in response to
electronic signals from the TCM/ECU. Lockup clutch engagement provides a
direct drive from the engine to the transmission gearing. This eliminates converter
slippage and maximizes fuel economy and vehicle speed. The lockup clutch
releases at lower speeds or when the TCM/ECU detects conditions requiring it to
be released.
The torsional damper absorbs engine torsional vibration to prevent transmitting
vibrations through the powertrain.
PLANETARY GEARS AND CLUTCHES
A series of three helical planetary gear sets and shafts provides the mechanical
gear ratios and direction of travel for the vehicle. The planetary gear sets are
controlled by five multiplate clutches that work in pairs to produce up to six
forward speeds and one reverse speed. The clutches are applied and released
hydraulically in response to electronic signals from the TCM/ECU to the
appropriate solenoids.
COOLER CIRCUIT
The transmission fluid is cooled by an integral (transmission-mounted) or
remote-mounted oil cooler. Connections to the cooling circuit are located at the
front or rear of the transmission to facilitate installation of remote cooler lines. On
retarder models, only the rear cooler ports may be used. The integral cooler is
mounted on the lower rear portion of the transmission, replacing the remote cooler
manifold. Integral cooler oil ports are internal requiring coolant to be routed to
and from the cooler.
A new feature has been added on all retarder-equipped transmissions. The retarder
housing now allows addition of either a remote or integral cooler for transmission
sump fluid in addition to retarder out fluid. A by-pass cover is placed over the
sump cooling ports when the provision is not used. The sump cooler ports are
located on the lower right rear face of the retarder housing (refer to Figure 1
through Figure 4).
14
RETARDER
The self-contained retarder is at the output of the transmission and consists of a
vaned rotor which rotates in a vaned cavity. The rotor is splined to and driven by
the output shaft. An external accumulator holds transmission fluid until the
retarder is activated. When the retarder is activated, the fluid in the accumulator is
pressurized by the vehicle air system and directed into the retarder cavity. The
interaction of the fluid with the rotating and stationary vanes causes the retarder
rotor and output shaft to reduce speed, slowing the vehicle or limiting speed on a
downhill grade. Refer to USING THE HYDRAULIC RETARDER for additional
information.
When the retarder is deactivated, the retarder cavity is evacuated and the
accumulator is recharged with fluid.
15
SHIFT SELECTORS
DESCRIPTION OF AVAILABLE TYPES
1
MODE
2
3
4
5
D
N
R
SIX-SPEED,
LEFT-HAND
LEVER
SELECTOR
HOLD OVERRIDE BUTTON
MODE INDICATOR
(LED)
MODE BUTTON
MODE ID
DIGITAL DISPLAY
*
DISPLAY MODE/
DIAGNOSTIC BUTTON
SIX-SPEED,
RIGHT-HAND
LEVER SELECTOR
WITH REVERSE TO FRONT
DIGITAL DISPLAY
*
R
MODE
N
D
5
4
3
2
1
HOLD OVERRIDE
BUTTON
MODE INDICATOR
(LED)
MODE BUTTON
MODE ID
DIGITAL DISPLAY
*
DISPLAY MODE/
DIAGNOSTIC BUTTON
MODE ID
MODE
R
N
D
MODE
INDICATOR (LED)
Push simultaneously
to enter diagnostic
mode and fluid
MODE
R
N
D
level check
PUSHBUTTON SELECTORS
NOTE:
Number displayed is highest forward range available in selected position.
*
Visually check to confirm range selected. If display is flashing, shift is inhibited.
R
MODE
N
D
5
4
3
2
1
CONTOURED
VERSION
V07343.01.02
Figure 5. WTEC III Shift Selectors
16
6
1
DIAGNOSTIC BUTTON
HOLD OVERRIDE
BUTTON
MODE INDICATOR
(LED)
MODE BUTTON
MODE ID
DIGITAL DISPLAY
DISPLAY MODE
*
HOLD OVERRIDE
BUTTON
MODE INDICATOR
6
1
MODE BUTTON
DIGITAL DISPLAY
DISPLAY MODE
DIAGNOSTIC BUTTON
(LED)
MODE ID
*
6
1
DIGITAL DISPLAY
MODE ID
MODE
The first number displayed is highest forward range available and second number is range
NOTE:
*
attained in selected position.
Visually check to confirm range selected. If display is flashing, shift is inhibited.
MODE
INDICATOR (LED)
Push simultaneously
to enter diagnostic
mode and fluid
level check
*
6
1
V07343.03.01
Figure 6. Allison 4thGeneration Controls Shift Selectors
INTRODUCTION
Vehicle manufacturers may choose different types of shift selectors for their
vehicles. The shift selector in your Allison-equipped vehicle will be similar to one
of the pushbutton or lever styles shown above.
With an Allison-equipped vehicle, it is not necessary to select the right moment to
upshift or downshift during changing road and traffic conditions. The Allison
Motorhome Series transmission does it for you. However, knowledge of the shift
selector positions, available ranges, and when to select them, make vehicle control
and your job even easier. Select lower ranges when descending long grades (with
or without retarder) to reduce wear on service brakes. Refer to the Range
Selection table at the end of this section for related information.
17
LEVER SHIFT SELECTOR
General Description. The lever shift selector (refer to Figure 5 and Figure 6) is
an electro-mechanical control. Typical lever positions are:
• R (Reverse)
• N (Neutral)
• D (Drive)
• Some number of lower forward range positions
Motorhome Series transmissions can be programmed to have four, five,orsix
forward ranges. Shift selector positions should agree with the programming of the
TCM/ECU unit.
The lever selector includes the following:
• HOLD OVERRIDE button
• MODE button
• Digital display
• DISPLAY MODE/DIAGNOSTIC button
HOLD OVERRIDE Button. The lever shift selector has three locked positions to
prevent accidentally selecting R (Reverse), N (Neutral), or D (Drive). Select
R (Reverse), N (Neutral), or D (Drive) by pressing the HOLD OVERRIDE
button and moving the lever to the desired position. Once D (Drive) is selected,
lower forward range positions may be selected without pressing the
HOLD OVERRIDE button.
MODE Button. The MODE button can allow the driver to enable a secondary
shift schedule, PTO, or other special functions that have been programmed into
the TCM/ECU unit at the request of the OEM. For example, a motorhome OEM
may have provided a secondary shift schedule for improved fuel economy. The
name of the special function (ECONOMY) appears on the MODE ID label
adjacent to the MODE button. Pressing the MODE button activates the
ECONOMY shift schedule and illuminates the MODE INDICATOR (LED).
When the Diagnostic Display Mode has been entered, the MODE button is used
to view and toggle through diagnostic code information. After viewing the first
diagnostic code which appears in the digital display, press the MODE button to
view the 2
and 5
nd
th
diagnostic code logged. Repeat this procedure to view the 3rd,4th,
code positions. The code displayed is active if the MODE INDICATOR
(LED) is illuminated.
NOTE: Visually check the digital display whenever the lever is moved
to be sure the range selected is shown. N should appear in the digital
displayiftheN (Neutral) button is pressed.
18
Digital Display. During normal operation, if D (Drive) is selected, the digital
display shows the highest forward range attainable for the shift schedule in use.
Abnormal operation is indicated by the WTEC III digital display as follows:
• When all segments of the digital display are illuminated for more than
12 seconds, the ECU did not complete initialization.
• When the digital display is blank, there is no power to the selector.
• When the display shows a “
\
/\” (cateye), a selector-related fault code has
been logged.
• Conditions which illuminate the CHECK TRANS light disable the shift
selector and the digital display displays the range actually attained. For a
detailed explanation, refer to the CHECK TRANS LIGHT paragraph in the
DRIVING TIPS section.
Abnormal operation is indicated by the Allison 4
th
Generation Controls digital
display as follows:
• When all segments of the digital display are illuminated, the shift selector
did not complete initialization.
• When both digital displays remain blank for 10 seconds after initialization
and then show a “
\
/\” (cateye), the shift selector is unable to communicate
with the TCM or has experienced an internal fault.
• When the display shows a “
\
/\” (cateye), a selector-related fault code has
been logged.
• Conditions which illuminate the CHECK TRANS light disable the shift
selector. The SELECT digit is blank and the MONITOR digit displays the
range actually attained. For a detailed explanation, refer to the CHECK
TRANS LIGHT paragraph in the DRIVING TIPS section.
The transmission will not shift into range if a CHECK TRANS code is active.
When the display shows R or D has been requested and the display is flashing,
the requested range has not been achieved due to an inhibit function.
Some inhibit functions are vehicle-related and do not result in diagnostic codes.
Some examples are mentioned in the Range Selection tables at the end of this
Section.
Check for active codes if no other inhibit function has been located. Once
D (Drive) is attained, the transmission will shift into the lowest range programmed
for the D (Drive) position, usually first-range.
Display Mode/Diagnostic Button. The DISPLAY MODE/DIAGNOSTIC button
allows access to optional fluid level check information and diagnostic code
information. Press the DISPLAY MODE/DIAGNOSTIC button once to obtain
transmission fluid level information and a second time to obtain diagnostic code
information.
19
PUSHBUTTON SHIFT SELECTOR
General Description. The pushbutton shift selector (refer to Figure 5 and
Figure 6) has the following:
• R (Reverse)—Press this button to select Reverse.
• N (Neutral)—Press this button to select Neutral.
• D (Drive)—Press this button to select Drive. The highest forward range
available will appear in the digital display window. The transmission will
start out in the lowest available forward range and advance automatically to
the highest range.
• ↑ (Up) Arrow—Press the ↑ (Up) Arrow when in DRIVE to request the
next higher range. Continuously pressing the ↑ (Up) Arrow will request the
highest range available.
• ↓ (Down) Arrow—Press the ↓ (Down) Arrow when in DRIVE to request
the next lower range. Continuously pressing the ↓ (Down) Arrow will
request the lowest range available.
• MODE Button and Display Mode/Diagnostic Button—This is the same
function as described previously in the LEVER SHIFT SELECTOR
paragraph, MODE Button paragraph.
NOTE: The oil level sensor is a standard feature on Motorhome Series
transmissions. Fluid level information is displayed after pressing both
the ↑ (Up) and ↓ (Down) arrow buttons simultaneously. Simultaneously
press both buttons again to obtain diagnostic data.
Refer to the Care And Maintenance section, FLUID LEVEL CHECK USING
PUSHBUTTON OR LEVER SHIFT SELECTOR for more information about fluid
level data. Refer to the Driving Tips section, DIAGNOSTIC CODES and
DIAGNOSTIC CODE DISPLAY PROCEDURE, for more information about
diagnostic codes and display procedure.
20
RANGE SELECTION
R
MODE
R
N
D
N
D
MODE
R
MODE
N
D
5
4
3
2
1
R
MODE
N
D
5
4
3
2
1
V07344
Figure 7. Typical Motorhome Series Shift Selectors
(WTEC III Controls)
MODE
Figure 8. Typical Motorhome Series Shift Selectors
(Allison 4
R
N
D
6
5
4
1
3
2
1
th
Generation Controls)
6
1
V07344.01.00
6
1
21
PUSHBUTTON AND LEVER SHIFT SELECTORS
WITH DIGITAL DISPLAY
Description of Available Ranges (refer to Figure 7 and Figure 8)
WARNING: If you leave the vehicle and the engine is running,
the vehicle can move unexpectedly and you or others could be
injured. If you must leave the engine running, do not leave the
vehicle until you have completed all of the following
procedures:
1. Put the transmission in N (Neutral).
2. Be sure the engine is at low idle (500–800 rpm).
3. Apply the parking brakes and emergency brake and make
sure they are properly engaged.
4. Chock the wheels and take any other steps necessary to
keep the vehicle from moving.
WARNING: R (Reverse) may not be attained due to an active
inhibitor. Always apply the service brakes when selecting
R (Reverse) to prevent unexpected vehicle movement and
because a service brake inhibit may be present. When “R” is
flashing, it indicates the shift to R (Reverse) is inhibited.
Check for active diagnostic codes if R (Reverse) is not
attained. See DOWNSHIFT AND DIRECTION CHANGE
INHIBITOR FEATURE in the DRIVING TIPS section.
CAUTION: Do not idle in R (Reverse) for more than
five minutes. Extended idling in R (Reverse) can cause
transmission overheating and damage. Always select N (Neutral)
whenever time at idle exceeds five minutes.
NOTE: Visually check the digital display window whenever a
button is pushed or the lever is moved to be sure the range selected
isshown(i.e.,iftheN (Neutral) button is pressed, “N” should
appear in the digital display). A flashing display indicates the range
selected was not attained due to an active inhibit.
22
PUSHBUTTON AND LEVER SHIFT SELECTORS
WITH DIGITAL DISPLAY
(cont’d)
Description of Available Ranges (refer to Figure 7 and Figure 8)
R Completely stop the vehicle and let the engine return to idle before
shifting from a forward range to R (Reverse) or from R (Reverse)
to a forward range. The digital display will display “R” when
R (Reverse) is selected.
WARNING: When starting the engine, make sure the service
brakes are applied. Failure to apply the service brakes can
result in unexpected vehicle movement.
WARNING: Vehicle service brakes, parking brake, or
emergency brake must be applied whenever N (Neutral) is
selected to prevent unexpected vehicle movement. Selecting
N (Neutral) does not apply vehicle brakes, unless an auxiliary
system to apply the parking brake is installed (see the
Operator’s Manual for the vehicle).
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).
N Use N (Neutral) when starting the engine, to check vehicle
accessories, and for extended periods of engine idle operation
(longer than five minutes). For vehicles equipped with the
pushbutton selector, N (Neutral) is selected by the ECU during
start-up. For vehicles equipped with the lever selector, the vehicle
will not start unless N (Neutral) has been selected. If the vehicle
starts in any range other than N (Neutral), seek service
immediately. N (Neutral) is also used during stationary operation of
the power takeoff (if the vehicle is equipped with a PTO). The
digital display will show “N” when N (Neutral) is selected. Always
select N (Neutral) before turning off the vehicle engine.
23
PUSHBUTTON AND LEVER SHIFT SELECTORS
WITH DIGITAL DISPLAY
(cont’d)
Description of Available Ranges (refer to Figure 7 and Figure 8)
WARNING: D (Drive) may not be attained due to an active
inhibitor. Always apply the service brakes when selecting
D (Drive) to prevent unexpected vehicle movement and
because a service inhibit may be present. When “D” is
flashing, it indicates the shift to D (Drive) is inhibited. Check
for active diagnostic codes if D (Drive) is not attained. See
DOWNSHIFT AND DIRECTION CHANGE INHIBITOR
FEATURE in the DRIVING TIPS section.
CAUTION: Do not idle in D (Drive) or any forward range for
more than five minutes. Extended idling in D (Drive) can cause
transmission overheating and damage. Always select N (Neutral)
whenever time at idle exceeds five minutes.
NOTE: Turn off the vehicle HIGH IDLE switch, if present, before
shifting from N (Neutral) to D (Drive) or R (Reverse). D (Drive)
or R (Reverse) will not be attained unless the shift is made with
the engine at idle. Also, be aware of other interlocks that would
prevent attaining D (Drive) or R (Reverse). Examples are
“wheelchair lift not stored” and “service brakes not applied”
(service brake interlock present).
D The transmission will initially attain first-range when D (Drive) is
selected (except for those units programmed to start in
second-range). As vehicle speed increases, the transmission will
upshift automatically through each range. As the vehicle slows, the
transmission will downshift automatically through each range. The
digital display will show the highest range available in D (Drive).
WARNING: The transmission incorporates a hold feature to
prohibit upshifting above the range selected during normal
driving. For downhill operation, select a lower transmission
range. If the engine governed speed is exceeded in the held
range, however, the transmission will upshift to the next higher
range to prevent engine damage. To avoid injury and/or property
damage due to loss of vehicle control, use the vehicle brakes to
prevent exceeding engine governed speed in the held range.
24
PUSHBUTTON AND LEVER SHIFT SELECTORS
WITH DIGITAL DISPLAY
(cont’d)
Description of Available Ranges (refer to Figure 7 and Figure 8)
6*
5*
4*
3
2
Lower ranges provide greater engine braking for going down
grades (the lower the range, the greater the braking effect).
Occasionally, it may be desirable to restrict automatic shifting to a
lower range because of:
• Road conditions.
• Load.
• Traffic conditions.
• Etc.
The pushbutton shift selector arrow buttons access individual
forward ranges. Push the ↑ (Up) or ↓ (Down) arrow for the desired
range. The digital display shows the range chosen. Even though a
lower range is selected, the transmission may not downshift until
vehicle speed is reduced (this prevents excessive engine speed in
the lower range).
1 First-range provides the vehicle with its maximum driving torque
and engine braking effect. Use first-range when:
• Pulling through mud and deep snow.
• Maneuvering in tight spaces.
• Driving up or down steep grades.
For vehicles equipped with the pushbutton selector, push the
↓ (Down) arrow until first-range appears in the select window.
* Actual ranges available depend on programming by vehicle manufacturer.
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DRIVING TIPS
CHECK TRANS LIGHT
The electronic control system is programmed to inform the operator of a problem
with the transmission system and automatically take action to protect the operator,
vehicle, and transmission. When the Electronic Control Unit (ECU) or the
Transmission Control Module (TCM) detects a problem condition, the TCM/ECU:
• Restricts shifting.
• Illuminates the CHECK TRANS light on the instrument panel.
• Registers a diagnostic code.
NOTE: For some problems, diagnostic codes may be registered without
the TCM/ECU activating the CHECK TRANS light. Your Allison
Transmission authorized service outlet should be consulted whenever
there is a transmission-related concern. They have the equipment to
check for diagnostic codes and to correct problems which arise.
Each time the engine is started, the CHECK TRANS light will illuminate, then
turn off after a few seconds. This momentary lighting is to show that the status
light circuits are working properly. If the CHECK TRANS light does not
illuminate during ignition, or if the light remains on after ignition, the system
should be checked immediately.
Continued illumination of the CHECK TRANS light during vehicle operation
(other than start-up) indicates that the TCM/ECU has signaled a diagnostic code.
Illumination of the CHECK TRANS light is accompanied by a flashing display
from the shift selector. The shift selector display will show the actual range
attained and the transmission will not respond to shift selector requests.
Indications from the shift selector are provided to inform the operator the
transmission is not performing as designed and is operating in the “limp home”
mode with reduced capabilities. Before turning off the ignition, the transmission
may be operated for a short time in the selected range in order to “limp home” for
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service assistance. Service should be performed immediately in order to minimize
the potential for damage to the transmission.
When the CHECK TRANS light comes on and the ignition switch is turned off,
the transmission will remain in N (Neutral) until the condition causing the
CHECK TRANS light is corrected.
Generally, while the CHECK TRANS light is on, upshifts and downshifts will be
restricted and direction changes will not occur. Lever and pushbutton shift
selectors do not respond to any operator shift requests while the CHECK
TRANS light is illuminated. The lockup clutch is disengaged when transmission
shifting is restricted or during any critical transmission malfunction.
DIAGNOSTIC CODES
See detailed information in the DIAGNOSTICS section.
ACCELERATOR CONTROL
WARNING: To help avoid injury or property damage caused by sudden
movement of the vehicle, do not make shifts from N (Neutral) to
D (Drive) or R (Reverse) when the throttle pedal is depressed. If you
shift while the throttle pedal is depressed too far, the transmission will
only engage if the throttle pedal is released in the next three seconds.
This may cause a sudden movement of the vehicle. Leaving the throttle
pedal depressed longer than three seconds causes the transmission to
remain in N (Neutral). Avoid this condition by making shifts from
N (Neutral) to D (Drive) or R (Reverse) only when the throttle is
closed.
The position of the accelerator pedal influences when automatic shifting occurs.
An electronic throttle position signal tells the TCM/ECU how much the operator
has depressed the pedal. When the pedal is fully depressed, upshifts will occur
automatically at high engine speeds. A partially depressed position of the pedal
will cause upshifts to occur at lower engine speeds. Excessive throttle position
affects directional changes—shifts from N (Neutral) to D (Drive) or R (Reverse).
DOWNSHIFT AND DIRECTION CHANGE INHIBITOR FEATURE
NOTE: Turn off the vehicle HIGH IDLE switch, if present, before
shifting from N (Neutral) to D (Drive) or R (Reverse). The shift from
N (Neutral) to D (Drive) or R (Reverse) is inhibited when engine speed
is above idle.
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There is no speed limitation on upshifting, but there is a limitation on
downshifting and for shifts that cause a direction change such as
D (Drive)-to-R (Reverse) or R (Reverse)-to-D (Drive).
Manual range downshifts will not occur until a calibration output speed (preset) is
reached. When a range downshift is manually selected and the transmission output
speed is above the calibration speed, the transmission will stay in the range it was
in even though a lower range was requested. Apply the vehicle service brakes or a
retarding device to reduce the transmission output speed to the calibration speed
and then the shift to the lower range will occur.
Directional shifts, D (Drive)-to-R (Reverse) or R (Reverse)-to-D (Drive), will not
occur if selected when throttle position, engine speed, or transmission output
speed is above the calibration limit for a calibration time period. The current
calibration time period for engine speed is 0.5 seconds and for throttle position
and output speed is three seconds.
Shifts from N (Neutral)-to-D (Drive) or N (Neutral)-to-R (Reverse) are also
inhibited when the TCM/ECU has been programmed (by input/output function) to
detect that auxiliary equipment is in operation and the shift should not be allowed.
When directional change shifts are inhibited, the TCM/ECU will put the
transmission in N (Neutral) and the digital display, if present, will flash the letter
of the range selected (D or R). To reselect D (Drive) or R (Reverse) when engine
throttle, engine speed, and transmission output speed are below the calibration
value:
• Pushbutton selector—Press the desired pushbutton again.
• Lever selector—Move the lever to N (Neutral) and then to the desired
range.
When a direction change shift is requested and engine throttle, engine speed, and
transmission output speed drop below the calibration value during the calibration
time interval, the shift to D (Drive) or R (Reverse) will occur.
For example, if the transmission output speed was just above the calibration limit
when R (Reverse) was selected, but dropped below the limit during the next three
seconds, the shift to R (Reverse) would occur (assuming the engine was at idle
and the throttle was closed).
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