
INSTALLATION
(1) Using Tool C-4193, install oil pump seal (Fig.
303).
(2) Install transaxle to vehicle (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC - 41TE
- INSTALLATION) .
SHIFT INTERLOCK SOLENOID
DESCRIPTION
The Brake/Transmission Shift Interlock system
consists of an electro-magnetic solenoid mounted to
the steering column (Fig. 304). The solenoid's plunger
consists of an integrated hook, which operates the
shift lever pawl (part of shift lever assembly), and a
plunger return spring (Fig. 305). The solenoid also
has an integrated bracket, which facilitates fastening
to the steering column.
Fig. 302 Remove Oil Pump Seal
1 - TOOL C-3981±B
2 - OIL PUMP SEAL
Fig. 303 Install Oil Pump Seal
1 - TOOL C-4193
2 - HANDLE TOOL C-4171
Fig. 304 Brake/Transmission Shift Interlock (BTSI)
Solenoid Location
1 - BTSI SOLENOID
Fig. 305 Solenoid Plunger and Return Spring
1 - PLUNGER
2 - RETURN SPRING
3 - BTSI SOLENOID
21 - 272 AUTOMATIC - 41TERS
SEAL - OIL PUMP (Continued)

OPERATION
The Brake/Transmission Shift Interlock (BTSI)
Solenoid prevents the transmission shift lever from
being moved out of PARK (P) unless the brake pedal
is applied. The BTSI solenoid is hardwired to and
controlled by the Intelligent Power Module (IPM).
Battery voltage is applied to one side of the solenoid
with the ignition key is in either the ON/RUN or
START positions (Fig. 306). The ground side of the
solenoid is controlled by a driver within the IPM. It
relies on voltage supplied from the stop lamp switch
to the stop lamp sense circuit within the IPM to tell
when the brake pedal is depressed. When the brake
pedal is depressed, the ground circuit opens, de-ener-
gizing the solenoid. When the brake pedal is
released, the ground circuit is closed, energizing the
solenoid.
When the ignition key is in either the ON/RUN or
START positions, the BTSI solenoid is energized, and
the solenoid plunger hook pulls the shift lever pawl
into position, prohibiting the shift lever from moving
out of PARK (P) (Fig. 307). When the brake pedal is
depressed, the ground circuit opens, de-energizing
the solenoid. This moves the gearshift lever pawl out
of the way (Fig. 308), allowing the shift lever to be
moved into any gear position.
A conventional mechanical interlock system is also
used. This system manually prohibits shifter move-
ment when the ignition switch is in the LOCK or
ACC positions. Solenoid operation is not required in
these key positions. When the ignition key is in the
OFF position, the gearshift lever is unrestricted, and
able to move into any gear position (during towing,
dead battery, etc.).
Fig. 306 Ignition Key/Switch Positions
1 - ACC
2 - LOCK
3 - OFF
4 - ON/RUN
5-START
Fig. 307 Pawl Engaged to Shift Lever
1 - GEAR SHIFT LEVER
2 - GEAR SHIFT LEVER PAWL
Fig. 308 Pawl Disengaged From Shift Lever
1 - GEAR SHIFT LEVER
2 - GEAR SHIFT LEVER PAWL
RSAUTOMATIC - 41TE21 - 273
SHIFT INTERLOCK SOLENOID (Continued)

For intended BTSI system operation, refer to the
following chart:
ACTION EXPECTED RESPONSE
1. Turn key to the9OFF9
position.1. Shifter CAN be shifted
out of park.
2. Turn key to the
9ON/RUN9position.2. Shifter CANNOT be
shifted out of park.
3. Turn key to the
9ON/RUN9position and
depress the brake pedal.3. Shifter CAN be shifted
out of park.
4. Leave shifter in any
gear and try to return key
to the9LOCK9or9ACC9
position.4. Key cannot be
returned to the9LOCK9or
9ACC9position.
5. Return shifter to
9PARK9and try to remove
the key.5. Key can be removed
(after returning to9LOCK9
position).
6. With the key removed,
try to shift out of9PARK9.6. Shifter cannot be
shifted out of9PARK9.
NOTE: Any failure to meet these expected
responses requires system adjustment or repair.
DIAGNOSIS AND TESTING - BRAKE/
TRANSMISSION SHIFT INTERLOCK SOLENOID
For intended BTSI system operation, refer to the
following chart:
ACTION EXPECTED RESPONSE
1. Turn key to the9OFF9
position.1. Shifter CAN be shifted
out of park.
2. Turn key to the
9ON/RUN9position.2. Shifter CANNOT be
shifted out of park.
3. Turn key to the
9ON/RUN9position and
depress the brake pedal.3. Shifter CAN be shifted
out of park.
4. Leave shifter in any
gear and try to return key
to the9LOCK9or9ACC9
position.4. Key cannot be
returned to the9LOCK9or
9ACC9position.
5. Return shifter to
9PARK9and try to remove
the key.5. Key can be removed
(after returning to9LOCK9
position).
6. With the key removed,
try to shift out of9PARK9.6. Shifter cannot be
shifted out of9PARK9.
NOTE: Any failure to meet these expected
responses requires system repair. Refer to the
appropriate Diagnostic Information.
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove instrument panel lower shroud (Fig.
309).
(3) Remove knee bolster (Fig. 310).
(4) Remove steering column lower shroud.
(5) Disconnect brake/transmission shift interlock
(BTSI) solenoid connector (Fig. 311).
(6) Remove two (2) solenoid-to-column screws (Fig.
312).
(7) Remove solenoid.
Fig. 309 Instrument Panel Lower Silencer
1 - INSTRUMENT PANEL LOWER SILENCER
Fig. 310 Knee Bolster
1 - KNEE BOLSTER
21 - 274 AUTOMATIC - 41TERS
SHIFT INTERLOCK SOLENOID (Continued)

INSTALLATION
(1) Place interlock solenoid into position ensuring
hook on end of solenoid plunger engages gearshift
lever pawl pin. Install and tighten screws (Fig. 313).
(2) Verify gearshift lever is in PARK (P) and con-
nect solenoid connector (Fig. 314).
Fig. 311 BTSI Solenoid Connector
1 - BTSI SOLENOID
2 - SOLENOID CONNECTOR
Fig. 312 Solenoid Retaining Screw
1 - SOLENOID RETAINING SCREW (2)
Fig. 313 Solenoid Retaining Screw
1 - SOLENOID RETAINING SCREW (2)
Fig. 314 BTSI Solenoid Connector
1 - BTSI SOLENOID
2 - SOLENOID CONNECTOR
RSAUTOMATIC - 41TE21 - 275
SHIFT INTERLOCK SOLENOID (Continued)

(3) Install steering column lower shroud.
(4) Install knee bolster (Fig. 315).
(5) Install instrument panel lower silencer (Fig.
316).
(6) Connect battery negative cable.
(7) Verify proper shift interlock system operation.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 31TH/SHIFT INTERLOCK SOLENOID -
OPERATION)SOLENOID/PRESSURE
SWITCH ASSEMBLY
DESCRIPTION
The Solenoid/Pressure Switch Assembly (Fig. 317)
is external to the transaxle and mounted to the
transaxle case. The assembly consists of four sole-
noids that control hydraulic pressure to the LR/CC,
2/4, OD, and UD friction elements. The reverse
clutch is controlled by line pressure from the manual
valve in the valve body. The solenoids are contained
within the Solenoid/Pressure Switch Assembly, and
can only be serviced by replacing the assembly.
The solenoid assembly also contains pressure
switches that monitor and send hydraulic circuit
information to the TCM. Likewise, the pressure
switches can only be service by replacing the assem-
bly.
OPERATION
SOLENOIDS
The solenoids receive electrical power from the
Transmission Control Relay through a single wire.
The TCM energizes or operates the solenoids individ-
ually by grounding the return wire of the solenoid
needed. When a solenoid is energized, the solenoid
valve shifts, and a fluid passage is opened or closed
(vented or applied), depending on its default operat-
Fig. 315 Knee Bolster
1 - KNEE BOLSTER
Fig. 316 Instrument Panel Lower Silencer
1 - INSTRUMENT PANEL LOWER SILENCERFig. 317 Solenoid/Pressure Switch Assembly
1 - SOLENOID AND PRESSURE SWITCH ASSEMBLY
21 - 276 AUTOMATIC - 41TERS
SHIFT INTERLOCK SOLENOID (Continued)

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)

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)

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)