2002 CHRYSLER CARAVAN coolant temperature

STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 236).
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.
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 converternecessary 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
(1) Remove transmission and torque converter
from vehicle. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 31TH - 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
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. 237). 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.
Fig. 236 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
RS31TH AUTOMATIC TRANSAXLE21 - 127
TORQUE CONVERTER (Continued)
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OPERATION
The converter impeller (Fig. 333) (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.
STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 334).
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 statorfrom 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.
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
Fig. 333 Torque Converter Fluid Operation
1 - APPLY PRESSURE 3 - RELEASE PRESSURE
2 - THE PISTON MOVES SLIGHTLY FORWARD 4 - THE PISTON MOVES SLIGHTLY REARWARD
RS41TE AUTOMATIC TRANSAXLE21 - 289
TORQUE CONVERTER (Continued)
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OPERATION
The Transmission Range Sensor (TRS) (Fig. 337)
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.
Since there are four switches, there are 16 possible
combinations of open and closed switches (codes).
Seven of these codes are related to gear position and
three are recognized as ªbetween gearº codes. This
results in six codes which should never occur. These
are called ªinvalidº codes. An invalid code will result
in a DTC, and the TCM will then determine the shift
lever position based on pressure switch data. This
allows reasonably normal transmission operation
with a TRS failure.
TRS SWITCH STATES
SLP T42 T41 T3 T1
PCL CL CL OP
RCL OP OP OP
NCL CL OP CL
ODOP OP OP CL
3OP OP CL OP
LCL OP CL CL
TRANSMISSION TEMPERATURE SENSOR
The TRS has an integrated thermistor (Fig. 338)
that the TCM uses to monitor the transmission's
sump temperature. Since fluid temperature can
affect transmission shift quality and convertor lock
up, the TCM requires this information to determine
which shift schedule to operate in. The PCM also
monitors this temperature data so it can energize the
vehicle cooling fan(s) when a transmission ªoverheatº
condition exists. If the thermistor circuit fails, the
TCM will revert to calculated oil temperature usage.
CALCULATED TEMPERATURE
A failure in the temperature sensor or circuit will
result in calculated temperature being substituted for
actual temperature. Calculated temperature is a pre-
dicted fluid temperature which is calculated from a
combination of inputs:
²Battery (ambient) temperature
²Engine coolant temperature
²In-gear run time since start-up
REMOVAL
(1) Remove valve body assembly from transaxle.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 41TE/VALVE BODY - REMOVAL)
(2) Remove transmission range sensor retaining
screw and remove sensor from valve body (Fig. 339).
(3) Remove TRS from manual shaft.
INSTALLATION
(1) Install transmission range sensor (TRS) to the
valve body and torque retaining screw (Fig. 339) to 5
N´m (45 in. lbs.).
(2) Install valve body to transaxle. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
41TE/VALVE BODY - INSTALLATION)
TRD LINK
DESCRIPTION
The Torque Reduction Link (TRD) is a wire
between the PCM and TCM that is used by the TCM
to request torque management. Torque management
controls or reduces torque output of the engine dur-
ing certain shift sequences, reducing torque applied
to the transaxle clutches.
OPERATION
The torque management signal is basically a
12-volt pull-up supplied by the PCM to the TCM over
the torque reduction link (TRD). Torque management
Fig. 339 Remove Transmission Range Sensor
1 - TRANSMISSION RANGE SENSOR
2 - MANUAL VALVE CONTROL PIN
3 - RETAINING SCREW
21 - 292 41TE AUTOMATIC TRANSAXLERS
TRANSMISSION RANGE SENSOR (Continued)
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(5) Remove battery tray (Fig. 17). Disconnect bat-
tery temperature sensor.
(6) Remove coolant recovery bottle from bracket.
(7) Remove coolant recovery bottle mounting
bracket (Fig. 18).
(8) Disconnect gearshift cables from shift levers/
cover assembly (Fig. 19).
(9) Remove gearshift cable retaining clips from
mounting bracket (Fig. 19). Remove cables and
secure out of way.(10) Remove three (3) right engine mount bracket-
to-transaxle bolts (Fig. 20).
Fig. 17 Battery Tray
1 - BATTERY TRAY
Fig. 18 Coolant Recovery Bottle Bracket
1 - COOLANT RECOVERY BOTTLE BRACKET
2 - NUT
3 - MOUNT BRACKET
Fig. 19 Gearshift Cables at Transaxle
1 - SELECTOR CABLE
2 - CABLE RETAINER
3 - CABLE RETAINER
4 - CROSSOVER CABLE
5 - MOUNT BRACKET
Fig. 20 Transaxle Right Mount and Bracket
1 - MOUNT BRACKET
2 - BOLT (3)
3 - MOUNT
4 - BOLT (1)
RST850 MANUAL TRANSAXLE21 - 321
T850 MANUAL TRANSAXLE (Continued)
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(14) Connect gearshift cables to shift levers/cover
assembly (Fig. 87). Install cables into position at
mount bracket and secure with retaining clips.
(15) Install coolant recovery bottle bracket (Fig.
88).(16) Install coolant recovery bottle to bracket.
(17) Connect battery temperature sensor and
install battery tray (Fig. 89).
(18) Install battery, hold-down clamp and nut (Fig.
90).
Fig. 87 Gearshift Cables at Transaxle
1 - SELECTOR CABLE
2 - CABLE RETAINER
3 - CABLE RETAINER
4 - CROSSOVER CABLE
5 - MOUNT BRACKET
Fig. 88 Coolant Recovery Bottle Bracket
1 - COOLANT RECOVERY BOTTLE BRACKET
2 - NUT
3 - MOUNT BRACKET
Fig. 89 Battery Tray
1 - BATTERY TRAY
Fig. 90 Battery and Hold-Down Clamp
1 - BATTERY
2 - HOLD-DOWN CLAMP
21 - 342 T850 MANUAL TRANSAXLERS
T850 MANUAL TRANSAXLE (Continued)
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(5)2.4L Gas models goto Step 10. 2.5L TD
Models:Install coolant recovery bottle bracket (Fig.
144).
(6) Install coolant recovery bottle to bracket.
(7) Connect battery temperature sensor to battery
tray. Install battery tray into position (Fig. 145).(8) Install battery, hold-down clamp, and nut (Fig.
146).
(9) Install battery thermal shield (Fig. 147).
Fig. 144 Coolant Recovery Bottle Bracket
1 - COOLANT RECOVERY BOTTLE BRACKET
2 - NUT
3 - MOUNT BRACKET
Fig. 145 Battery Tray
1 - BATTERY TRAY
Fig. 146 Battery and Hold-Down Clamp
1 - BATTERY
2 - HOLD-DOWN CLAMP
Fig. 147 Battery Thermal Shield
1 - BATTERY THERMAL SHIELD
21 - 364 T850 MANUAL TRANSAXLERS
GEARSHIFT CABLE - CROSSOVER (Continued)
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(10)2.4L Gas models goto Step 15. 2.5L TD
Models:Remove battery thermal shield (Fig. 167).
(11) Remove battery hold down nut, clamp, and
battery (Fig. 168).(12) Remove battery tray (Fig. 169). Disconnect
battery temperature sensor.
(13) Remove coolant recovery bottle from bracket.
(14) Remove coolant recovery bottle mounting
bracket (Fig. 170).
Fig. 167 Battery Thermal Shield
1 - BATTERY THERMAL SHIELD
Fig. 168 Battery and Hold-Down Clamp
1 - BATTERY
2 - HOLD-DOWN CLAMP
Fig. 169 Battery Tray
1 - BATTERY TRAY
Fig. 170 Coolant Recovery Bottle Bracket
1 - COOLANT RECOVERY BOTTLE BRACKET
2 - NUT
3 - MOUNT BRACKET
21 - 370 T850 MANUAL TRANSAXLERS
GEARSHIFT CABLE - SELECTOR (Continued)
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(6) Install coolant recovery bottle to bracket.
(7) Connect battery temperature sensor to battery
tray. Install battery tray into position (Fig. 174).
(8) Install battery, hold-down clamp, and nut (Fig.
175).(9) Install battery thermal shield (Fig. 176).
(10) Install selector cable to gearshift mechanism
(Fig. 177). Install retainer clip (Fig. 178).
Fig. 174 Battery Tray
1 - BATTERY TRAY
Fig. 175 Battery and Hold-Down Clamp
1 - BATTERY
2 - HOLD-DOWN CLAMP
Fig. 176 Battery Thermal Shield
1 - BATTERY THERMAL SHIELD
Fig. 177 Selector Cable at Gearshift Mechanism
1 - GEARSHIFT MECHANISM
2 - SELECTOR CABLE
21 - 372 T850 MANUAL TRANSAXLERS
GEARSHIFT CABLE - SELECTOR (Continued)
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