41TE AUTOMATIC TRANSAXLE
INDEX
page page
GENERAL INFORMATION
41TE FOUR SPEED AUTOMATIC TRANSAXLE . 71
FLUID LEVEL AND CONDITION............. 72
SELECTION OF LUBRICANT............... 72
SPECIAL ADDITIVES..................... 72
DESCRIPTION AND OPERATION
ADAPTIVE CONTROLS................... 73
CLUTCH AND GEAR..................... 72
ELECTRONICS......................... 73
GEARSHIFT AND PARKING LOCK CONTROLS . 74
HYDRAULICS........................... 73
ON-BOARD DIAGNOSTICS................ 74
SENSORS............................. 73
SHIFT POSITION INDICATOR.............. 74
SOLENOIDS............................ 73
TORQUE MANAGEMENT.................. 74
TRANSMISSION CONTROL MODULE........ 74
TRANSMISSION RANGE SENSOR........... 74
DIAGNOSIS AND TESTING
41TE TRANSAXLE GENERAL DIAGNOSIS..... 75
CLUTCH AIR PRESSURE TESTS............ 77
FLUID LEAKAGE-TORQUE CONVERTER
HOUSING AREA....................... 78
HYDRAULIC PRESSURE TESTS............ 75
ROAD TEST............................ 75
SHIFT POSITION INDICATOR.............. 78
SERVICE PROCEDURES
ALUMINUM THREAD REPAIR.............. 81
FLUID AND FILTER CHANGE............... 79
FLUID DRAIN AND REFILL................. 81
FLUSHING COOLERS AND TUBES.......... 81OIL PUMP VOLUME CHECK............... 82
PINION FACTOR PROCEDURE............. 83
TRANSAXLE QUICK LEARN PROCEDURE.... 82
REMOVAL AND INSTALLATION
GEARSHIFT CABLE...................... 83
MANUAL VALVE LEVER (SHIFT LEVER)...... 84
OIL PUMP SEAL......................... 92
SOLENOID ASSEMBLY-REPLACE........... 85
SPEED SENSOR-INPUT................... 86
SPEED SENSOR-OUTPUT................. 86
TRANSAXLE........................... 89
TRANSMISSION CONTROL MODULE........ 87
TRANSMISSION RANGE SENSOR........... 85
VALVE BODY........................... 88
DISASSEMBLY AND ASSEMBLY
DIFFERENTIAL REPAIR.................. 139
INPUT CLUTCHES-RECONDITION.......... 110
TRANSAXLE ASSEMBLE................. 122
TRANSAXLE DISASSEMBLE............... 95
VALVE BODY RECONDITION............... 92
CLEANING AND INSPECTION
CLEANING VALVE BODY................. 144
ADJUSTMENTS
GEARSHIFT CABLE ADJUSTMENT......... 144
SCHEMATICS AND DIAGRAMS
41TE TRANSAXLE HYDRAULIC SCHEMATICS . 145
SPECIFICATIONS
41TE AUTOMATIC TRANSAXLE............ 158
41TE TORQUE SPECIFICATIONS.......... 158
SPECIAL TOOLS
41TE AUTOMATIC TRANSAXLE............ 159
GENERAL INFORMATION
41TE FOUR SPEED AUTOMATIC TRANSAXLE
The 41TE four-speed FWD transaxle uses fully-
adaptive controls. Adaptive controls are those which
perform their functions based on real-time feedback
sensor information. The transaxle uses hydraulically
applied clutches to shift a planetary gear train.
TRANSAXLE IDENTIFICATION
The 41TE transaxle identification code is printed
on a label. The label is located on the transaxle case
next to the solenoid assembly (Fig. 1).
Fig. 1 Identification Tag Location
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 71
CAUTION: Some clutch packs appear similar, but
they are not the same. Do not interchange clutch
components, as they might fail.
HYDRAULICS
The hydraulics of the transaxle provide:
²Manual shift lever select function
²Main line pressure regulation
²Torque converter and cooler flow control
Oil flow to the friction elements is controlled
directly by four solenoid valves. The hydraulics also
include a unique logic- controlled solenoid torque con-
verter clutch control valve. This valve locks out the
1st gear reaction element with the application of 2nd,
direct, or overdrive gear elements. It also redirects
the 1st gear solenoid output so that it can control
torque converter clutch operation. To regain access to
1st gear, a sequence of commands must be used to
move the solenoid TCC control valve. This precludes
any application of the 1st gear reaction element with
other elements applied. It also allows one solenoid to
control two friction elements.
Small, high-rate accumulators are provided in each
controlled friction element circuit. These serve to
absorb the pressure responses, and allow the controls
to read and respond to changes that are occurring.
SOLENOIDS
The solenoid valves perform most control functions,
these valves must be extremely durable and tolerant
of dirt. For that reason hardened-steel poppet and
ball valves are used. These are free from any close
operating clearances. The solenoids operate the
valves directly without any intermediate element.
Direct operation means that these units must have
very high output. They must close against the size-
able flow areas and high line pressures. Fast
response is also required to meet the control require-
ments.
Two of the solenoids are normally-venting and two
are normally-applying; this was done to provide a
default mode of operation. With no electrical power,
the transmission provides 2nd gear in (OD), (3), or
(L) shift lever positions. All other transmission lever
positions will operate normally. The choice of 2nd
gear was made to provide adequate breakaway per-
formance while still accommodating highway speeds.
SENSORS
There are three pressure switches to identify sole-
noid application. There are two speed sensors to read
input (torque converter turbine) and output (parking
sprag) speeds. There is also a transmission range
sensor to indicate the manual shift lever position.
The pressure switches are incorporated in an assem-
bly with the solenoids. Engine speed, throttle posi-tion, temperature, etc., are also observed. Some of
these signals are read directly from the engine con-
trol sensors; others are read from a multiplex circuit
with the powertrain control module.
ELECTRONICS
The 41TE Transmission Control Module (TCM) is
located underhood in a potted, die-cast aluminum
housing. The module used is a new controller called
EATX III. The TCM has a sealed, 60-way connector.
ADAPTIVE CONTROLS
These controls function by reading the input and
output speeds over 140 times a second and respond-
ing to each new reading. This provides the precise
and sophisticated friction element control needed to
make smooth clutch-to-clutch shifts for all gear
changes. The use of overrunning clutches or other
shift quality aids are not required. As with most
automatic transaxles, all shifts involve releasing one
element and applying a different element. In simpli-
fied terms, the upshift logic allows the releasing ele-
ment to slip backwards slightly. This ensures that it
does not have excess capacity. The apply element is
filled until it begins to make the speed change to the
higher gear. The apply pressure is then controlled to
maintain the desired rate of speed change. This con-
tinues until the shift is made. The key to providing
excellent shift quality is precision. For example, the
release element for upshifts is allowed to slip back-
wards slightly. The amount of that slip is typically
less than a total of 20 degrees. To achieve that pre-
cision, the TCM learns the traits of the transaxle
that it is controlling. It learns the release rate of the
releasing element and the apply time of the applying
element. It also learns the rate at which the apply
element builds pressure sufficient to begin making
the speed change. This method achieves more preci-
sion than would be possible with exacting tolerances.
It can also adapt to any changes that occur with age
or environment.
For kickdown shifts, the control logic allows the
releasing element to slip. Then controls the rate at
which the input (and engine) accelerate. When the
lower gear speed is achieved, the releasing element
reapplies to maintain that speed until the apply ele-
ment is filled. This provides quick response since the
engine begins to accelerate immediately. This also
provides a smooth torque exchange since the release
element can control the rate of torque increase. This
control can make any powertrain feel more respon-
sive without increasing harshness.
Adaptive controls respond to input speed changes.
They compensate for changes in engine or friction
element torque and provide good, consistent shift
quality for the life of the transaxle.
NSTRANSAXLE AND POWER TRANSFER UNIT 21 - 73
DESCRIPTION AND OPERATION (Continued)
TORQUE MANAGEMENT
Most 41TE transaxles utilize torque management.
Torque management is a unique function of the Pow-
ertrain Control Module (PCM). The PCM receives
output signals from the Transmission Control Module
(TCM) and many various engine sensors. The PCM
evaluates these signals and decides if it is necessary
to decrease the output of the engine's torque. This
reduction in torque does not interfere with the nor-
mal operation of the vehicle. This reduction in torque
will prolong the life of the drivetrain components.
Torque reduction is not noticeable in normal driving
functions. The torque reduction function shuts off
above 16 MPH.
ON-BOARD DIAGNOSTICS
This vehicle utilizes a diagnostic system called
OBDII. The powertrain control module communicates
with the Transmission Control Module. Whenever
the transaxle sets a fault in the Transmission Con-
trol Module (dependent on which fault is set), the
powertrain control module will turn on a MIL (Mal-
function Indicator Lamp) on the instrument cluster.
By reading the code in the powertrain control module
it will tell you where the fault occurred. If the fault
occurred in the transaxle, the controller will read a
CODE 45.For further information regarding OBDII,
refer to Group 25, Emission Systems.
These controls provide comprehensive, on-board
transaxle diagnostics. The information available can
aid in transaxle diagnosis. For example, apply ele-
ment buildup rate indicates solenoid performance.
Also included are self diagnostic functions. Self diag-
nostics allow the technician to test the condition of
the electronic controls. The Transmission Control
Module continuously monitors its critical functions. It
also records any malfunctions, and the number of
engine starts since the last malfunction. This allows
the technician to use the information in the event of
a customer complaint.
TRANSMISSION CONTROL MODULE
Do not interchange Transmission Control Modules
with previous year transmission control modules. If a
same year TCM is being used from a different vehi-
cle, the following procedures must be performed:
²Quick Learn Procedure
²Electronic Pinion Factor Procedure
The Transmission Control Module is located on the
right inner fender panel, in the engine compartment.
It is held in place by four mounting screws.NOTE: If the Transmission Control Module has
been replaced, the following procedures must be
performed:
²Quick Learn Procedure: This procedure will
allow the transmission control module to learn the
characteristics of the vehicle.
²Electronic Pinion Factor Procedure: This proce-
dure will reprogram the TCM to compensate for dif-
ferent tire sizes and final drive ratios.
GEARSHIFT AND PARKING LOCK CONTROLS
The transaxle is controlled by a lever type gear-
shift incorporated within the steering column. The
control has six selector lever positions: P (park), R
(reverse), N (neutral), and D (drive), 2 (second), and
1 (first). The parking lock is applied by moving the
selector lever past a gate to the P position.Do not
apply the parking lock until the vehicle has
stopped; otherwise, a severe ratchet noise will
occur.
TRANSMISSION RANGE SENSOR
The 41TE transaxle is equipped with a transmis-
sion range sensor that is located on top of the valve
body. This sensor will allow for accurate transmission
gear position measurement.
To service the transmission range sensor (TRS),
you must remove the valve body. For repair proce-
dures, refer to the Removal and Installation section
within this group.
Also located within the TRS is a transmission tem-
perature sensor. This sensor is used to measure the
transmission fluid sump temperature. The transmis-
sion temperature sensor is serviced with the TRS as
a unit.
SHIFT POSITION INDICATOR
The shifter position indicator is located in the
instrument cluster. The shifter position indicator out-
lines with a box the gear position the transaxle man-
ual valve lever is in.
The transmission range sensor (located on the
valvebody) sends a signal to the TCM on the position
of the transaxle manual valve lever. The TCM
receives the switch signal and processes the data.
The TCM sends the Shift Lever Position (SLP) infor-
mation to the BCM via the CCD bus. The BCM then
outlines with a box the appropriate shifter position
indicator in the instrument cluster.
To replace the shifter position indicator, refer to
Group 8E, Instrument Panel And Gauges.
21 - 74 TRANSAXLE AND POWER TRANSFER UNITNS
DESCRIPTION AND OPERATION (Continued)