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SPEED SENSOR - OUTPUT
DESCRIPTION
The Output Speed Sensor is a two-wire magnetic
pickup device that generates an AC signal as rotation
occurs. It is threaded into the transaxle case (Fig.
326) , sealed with an o-ring (Fig. 327), and is consid-
ered a primary input to the Transmission Control
Module (TCM).
OPERATION
The Output Speed Sensor provides information on
how fast the output shaft is rotating. As the rear
planetary carrier park pawl lugs pass by the sensor
coil (Fig. 328) , an AC voltage is generated and sent
to the TCM. The TCM interprets this information as
output shaft rpm.
The TCM compares the input and output speed
signals to determine the following:
²Transmission gear ratio
²Speed ratio error detection
²CVI calculation
VEHICLE SPEED SIGNAL
The vehicle speed signal is taken from the Output
Speed Sensor. The TCM converts this signal into a
pulse per mile signal and sends it to the PCM. The
PCM, in turn, sends the vehicle speed message
across the communication bus to the BCM. The BCM
sends this signal to the Instrument Cluster to dis-
play vehicle speed to the driver. The vehicle speed
signal pulse is roughly 8000 pulses per mile.
REMOVAL
(1) Disconnect battery negative cable.
(2) Raise vehicle on hoist.
(3) Disconnect output speed sensor connector.
(4) Unscrew and remove output speed sensor (Fig.
329).
(5) Inspect speed sensor o-ring (Fig. 330) and
replace if necessary.
Fig. 326 Output Speed Sensor
1 - OUTPUT SPEED SENSOR
Fig. 327 O-Ring Location
1 - OUTPUT SPEED SENSOR
2 - O-RING
Fig. 328 Sensor Relation to Planet Carrier Park Pawl
1 - OUTPUT SPEED SENSOR
2 - REAR PLANET CARRIER/OUTPUT SHAFT ASSEMBLY
3 - TRANSAXLE CASE
21 - 280 AUTOMATIC - 41TERS
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INSTALLATION
(1) Verify o-ring is installed into position (Fig.
330).
(2) Install and tighten input speed sensor to 27
N´m (20 ft. lbs.).
(3) Connect speed sensor connector.
(4) Connect battery negative cable.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 331) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid. If the fluid
is contaminated, flush the fluid cooler and lines.
Fig. 329 Output Speed Sensor
1 - OUTPUT SPEED SENSOR
Fig. 330 O-ring Location
1 - OUTPUT SPEED SENSOR
2 - O-RING
Fig. 331 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - CONVERTER CLUTCH DISC
6 - DRIVE PLATE
RSAUTOMATIC - 41TE21 - 281
SPEED SENSOR - OUTPUT (Continued)
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IMPELLER
The impeller (Fig. 332) is an integral part of the
converter housing. The impeller consists of curved
blades placed radially along the inside of the housing
on the transmission side of the converter. As the con-
verter housing is rotated by the engine, so is the
impeller, because they are one and the same and are
the driving member of the system.
TURBINE
The turbine (Fig. 333) is the output, or driven,
member of the converter. The turbine is mounted
within the housing opposite the impeller, but is not
attached to the housing. The input shaft is inserted
through the center of the impeller and splined into
the turbine. The design of the turbine is similar to
the impeller, except the blades of the turbine are
curved in the opposite direction.
Fig. 332 Impeller
1 - ENGINE FLEXPLATE
2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE
SECTION
3 - IMPELLER VANES AND COVER ARE INTEGRAL4 - ENGINE ROTATION
5 - ENGINE ROTATION
21 - 282 AUTOMATIC - 41TERS
TORQUE CONVERTER (Continued)
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STATOR
The stator assembly (Fig. 334) is mounted on a sta-
tionary shaft which is an integral part of the oil
pump. The stator is located between the impeller and
turbine within the torque converter case (Fig. 335).
The stator contains an over-running clutch, which
allows the stator to rotate only in a clockwise direc-
tion. When the stator is locked against the over-run-
ning clutch, the torque multiplication feature of the
torque converter is operational.
TORQUE CONVERTER CLUTCH (TCC)
The TCC (Fig. 336) was installed to improve the
efficiency of the torque converter that is lost to the
slippage of the fluid coupling. Although the fluid cou-
pling provides smooth, shock±free power transfer, it
is natural for all fluid couplings to slip. If the impel-
ler and turbine were mechanically locked together, a
zero slippage condition could be obtained. A hydraulic
piston was added to the turbine, and a friction mate-
rial was added to the inside of the front cover to pro-
vide this mechanical lock-up.
Fig. 333 Turbine
1 - TURBINE VANE
2 - ENGINE ROTATION
3 - INPUT SHAFT
4 - PORTION OF TORQUE CONVERTER COVER5 - ENGINE ROTATION
6 - OIL FLOW WITHIN TURBINE SECTION
RSAUTOMATIC - 41TE21 - 283
TORQUE CONVERTER (Continued)
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OPERATION
The converter impeller (Fig. 337) (driving member),
which is integral to the converter housing and bolted
to the engine drive plate, rotates at engine speed.
The converter turbine (driven member), which reacts
from fluid pressure generated by the impeller, rotates
and turns the transmission input shaft.
TURBINE
As the fluid that was put into motion by the impel-
ler blades strikes the blades of the turbine, some of
the energy and rotational force is transferred into the
turbine and the input shaft. This causes both of them
(turbine and input shaft) to rotate in a clockwise
direction following the impeller. As the fluid is leav-
ing the trailing edges of the turbine's blades it con-
tinues in a ªhinderingº direction back toward the
impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a
direction that it would tend to slow it down.
Fig. 334 Stator Components
1 - CAM (OUTER RACE)
2 - ROLLER
3 - SPRING
4 - INNER RACE
Fig. 335 Stator Location
1-STATOR
2 - IMPELLER
3 - FLUID FLOW
4 - TURBINE
Fig. 336 Torque Converter Clutch (TCC)
1 - IMPELLER FRONT COVER
2 - THRUST WASHER ASSEMBLY
3 - IMPELLER
4-STATOR
5 - TURBINE
6 - PISTON
7 - FRICTION DISC
21 - 284 AUTOMATIC - 41TERS
TORQUE CONVERTER (Continued)
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STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 338).
Under stall conditions (the turbine is stationary), the
oil leaving the turbine blades strikes the face of the
stator blades and tries to rotate them in a counter-
clockwise direction. When this happens the over±run-
ning clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes
the stator blades and is redirected into a ªhelpingº
direction before it enters the impeller. This circula-
tion of oil from impeller to turbine, turbine to stator,
and stator to impeller, can produce a maximum
torque multiplication of about 2.4:1. As the turbine
begins to match the speed of the impeller, the fluid
that was hitting the stator in such as way as to
cause it to lock±up is no longer doing so. In this con-
dition of operation, the stator begins to free wheel
and the converter acts as a fluid coupling.
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and
turbine are rotating at about the same speed and the
stator is freewheeling, providing no torque multipli-
cation. By applying the turbine's piston to the front
cover's friction material, a total converter engage-ment can be obtained. The result of this engagement
is a direct 1:1 mechanical link between the engine
and the transmission.
Fig. 337 Torque Converter Fluid Operation
1 - APPLY PRESSURE
2 - THE PISTON MOVES SLIGHTLY FORWARD3 - RELEASE PRESSURE
4 - THE PISTON MOVES SLIGHTLY REARWARD
Fig. 338 Stator Operation
1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES
RSAUTOMATIC - 41TE21 - 285
TORQUE CONVERTER (Continued)
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The engagement and disengagement of the TCC
are automatic and controlled by the Powertrain Con-
trol Module (PCM). The engagement cannot be acti-
vated in the lower gears because it eliminates the
torque multiplication effect of the torque converter
necessary for acceleration. Inputs that determine
clutch engagement are: coolant temperature, vehicle
speed and throttle position. The torque converter
clutch is engaged by the clutch solenoid on the valve
body. The clutch will engage at approximately 56
km/h (35 mph) with light throttle, after the shift to
third gear.
REMOVAL
NOTE: If torque conveter assembly is being
replaced, it is necessary to restart the TCC Break-In
Strategy. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/TRANSMISSION CONTROL
MODULE - STANDARD PROCEDURE)
(1) Remove transmission and torque converter
from vehicle. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 41TE - REMOVAL)
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
INSTALLATION
NOTE: If torque conveter is being replaced, it is
necessary to restart the TCC Break-In Strategy.
(Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/TRANSMISSION CONTROL MODULE -
STANDARD PROCEDURE)
Check converter hub and drive notches for sharp
edges, burrs, scratches, or nicks. Polish the hub and
notches with 320/400 grit paper or crocus cloth if nec-
essary. The hub must be smooth to avoid damaging
the pump seal at installation.
(1) Lubricate converter hub and oil pump seal lip
with transmission fluid.
(2) Place torque converter in position on transmis-
sion.CAUTION: Do not damage oil pump seal or bushing
while inserting torque converter into the front of the
transmission.
(3) Align torque converter to oil pump seal open-
ing.
(4) Insert torque converter hub into oil pump.
(5) While pushing torque converter inward, rotate
converter until converter is fully seated in the oil
pump gears.
(6) Check converter seating with a scale and
straightedge (Fig. 339). Surface of converter lugs
should be 1/2 in. to rear of straightedge when con-
verter is fully seated.
(7) If necessary, temporarily secure converter with
C-clamp attached to the converter housing.
(8) Install the transmission in the vehicle. (Refer
to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC
- 41TE - INSTALLATION)
(9) Fill the transmission with the recommended
fluid. (Refer to 21 - TRANSMISSION/TRANSAXLE/
AUTOMATIC - 41TE/FLUID - STANDARD PROCE-
DURE)
(10) If torque conveter was replaced, it is neces-
sary to reset the TCC Break-In Strategy. (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/TRANSMISSION CONTROL MODULE -
STANDARD PROCEDURE)
Fig. 339 Checking Torque Converter Seating
1 - SCALE
2 - STRAIGHTEDGE
21 - 286 AUTOMATIC - 41TERS
TORQUE CONVERTER (Continued)
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TRANSMISSION CONTROL
RELAY
DESCRIPTION
The transmission control relay (Fig. 340) is located
in the Intelligent Power Module (IPM), which is
located on the left side of the engine compartment
between the battery and left fender.
OPERATION
The relay is supplied fused B+ voltage, energized
by the TCM, and is used to supply power to the sole-
noid pack when the transmission is in normal oper-
ating mode. When the relay is ªoffº, no power is
supplied to the solenoid pack and the transmission is
in ªlimp-inº mode. After a controller reset (ignition
key turned to the ªrunº position or after cranking
engine), the TCM energizes the relay. Prior to this,
the TCM verifies that the contacts are open by check-
ing for no voltage at the switched battery terminals.
After this is verified, the voltage at the solenoid pack
pressure switches is checked. After the relay is ener-
gized, the TCM monitors the terminals to verify that
the voltage is greater than 3 volts.
TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) is mounted
to the top of the valve body inside the transaxle and
can only be serviced by removing the valve body. The
electrical connector extends through the transaxle
case (Fig. 341) .
The Transmission Range Sensor (TRS) has four
switch contacts that monitor shift lever position and
send the information to the TCM.
The TRS also has an integrated temperature sen-
sor (thermistor) that communicates transaxle tem-
perature to the TCM and PCM (Fig. 342) .
OPERATION
The Transmission Range Sensor (TRS) (Fig. 341)
communicates shift lever position (SLP) to the TCM
as a combination of open and closed switches. Each
shift lever position has an assigned combination of
switch states (open/closed) that the TCM receives
from four sense circuits. The TCM interprets this
information and determines the appropriate trans-
axle gear position and shift schedule.
Fig. 340 Transmission Control Relay Location
1 - TRANSMISSION CONTROL RELAY
2 - LEFT FENDER
3 - INTELLIGENT POWER MODULE (IPM)
4 - BATTERYFig. 341 Transmission Range Sensor (TRS)
Location
1 - TRANSMISSION RANGE SENSOR
RSAUTOMATIC - 41TE21 - 287
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