2002 JEEP GRAND CHEROKEE Gear

(6) Install front thrust washer on rear planetary
gear (Fig. 210). Use enough petroleum jelly to hold
washer on gear. Be sure all four washer tabs are
seated in slots.
(7) Install spacer on sun gear (Fig. 211).
(8) Install thrust plate on sun gear (Fig. 212). Note
that driving shell thrust plates are interchangeable.
Use either plate on sun gear and at front/rear of
shell.
(9) Hold sun gear in place and install thrust plate
over sun gear at rear of driving shell (Fig. 213).
(10) Position wood block on bench and support sun
gear on block (Fig. 214). This makes it easier to align
and install sun gear lock ring. Keep wood block
handy as it will also be used for geartrain end play
check.
Fig. 208 Assembling Rear Annulus And Planetary
Gear
1 - REAR ANNULUS GEAR
2 - TABBED THRUST WASHER
3 - REAR PLANETARY
Fig. 209 Installing Rear Annulus And Planetary On
Output Shaft
1 - REAR ANNULUS AND PLANETARY GEAR ASSEMBLY
2 - OUTPUT SHAFT
Fig. 210 Installing Rear Planetary Front Thrust
Washer
1 - FRONT TABBED THRUST WASHER
2 - REAR PLANETARY GEAR
Fig. 211 Installing Spacer On Sun Gear
1 - SUN GEAR
2 - SUN GEAR SPACER
21 - 114 AUTOMATIC TRANSMISSION - 42REWJ
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(11) Align rear thrust plate on driving shell and
install sun gear lock ring. Be sure ring is fully seated
in sun gear ring groove (Fig. 215).
(12) Install assembled driving shell and sun gear
on output shaft (Fig. 216).
(13) Install rear thrust washer on front planetary
gear (Fig. 217). Use enough petroleum jelly to hold
washer in place and be sure all four washer tabs are
seated.
Fig. 212 Installing Driving Shell Front Thrust Plate
On Sun Gear
1 - SPACER
2 - SUN GEAR
3 - THRUST PLATE
Fig. 213 Installing Driving Shell Rear Thrust Plate
1 - DRIVING SHELL
2 - SUN GEAR
3 - REAR THRUST PLATE
Fig. 214 Supporting Sun Gear On Wood Block
1 - SUN GEAR
2 - DRIVING SHELL
3 - WOOD BLOCK
Fig. 215 Installing Sun Gear Lock Ring
1 - LOCK RING GROOVE
2 - SUN GEAR LOCK RING
3 - DRIVING SHELL
4 - REAR THRUST PLATE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 115
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(14) Install front planetary gear on output shaft
and in driving shell (Fig. 218).
(15) Install front thrust washer on front planetary
gear. Use enough petroleum jelly to hold washer in
place and be sure all four washer tabs are seated.
(16) Assemble front annulus gear and support, if
necessary. Be sure support snap-ring is seated.(17) Install front annulus on front planetary (Fig.
218).
(18) Position thrust plate on front annulus gear
support (Fig. 219). Note that plate has two tabs on it.
These tabs fit in notches of annulus hub.
(19) Install thrust washer in front annulus (Fig.
220). Align flat on washer with flat on planetary hub.
Also be sure washer tab is facing up.
(20) Install front annulus snap-ring (Fig. 221). Use
snap-ring pliers to avoid distorting ring during
installation. Also be sure ring is fully seated.
(21) Install planetary selective snap-ring with
snap-ring pliers (Fig. 222). Be sure ring is fully
seated.
(22) Turn planetary geartrain assembly over so
driving shell is facing workbench. Then support
geartrain on wood block positioned under forward
end of output shaft. This allows geartrain compo-
nents to move forward for accurate end play check.
(23) Check planetary geartrain end play with
feeler gauge (Fig. 223). Gauge goes between shoulder
on output shaft and end of rear annulus support.
(24) Geartrain end play should be 0.12 to 1.22 mm
(0.005 to 0.048 in.). If end play is incorrect, snap-ring
(or thrust washers) may have to be replaced. Snap-
rings are available in three different thicknesses for
adjustment purposes.
Fig. 216 Installing Assembled Sun Gear And Driving
Shell On Output Shaft
1 - SUN GEAR/DRIVING SHELL ASSEMBLY
2 - OUTPUT SHAFT
Fig. 217 Installing Rear Thrust Washer On Front
Planetary Gear
1 - FRONT PLANETARY GEAR
2 - REAR TABBED THRUST WASHER
Fig. 218 Installing Front Planetary And Annulus
Gears
1 - FRONT PLANETARY GEAR
2 - FRONT THRUST WASHER
3 - FRONT ANNULUS GEAR
21 - 116 AUTOMATIC TRANSMISSION - 42REWJ
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

Fig. 219 Positioning Thrust Plate On Front Annulus
Support
1 - FRONT ANNULUS
2 - THRUST PLATE
Fig. 220 Installing Front Annulus Thrust Washer
1 - WASHER FLAT ALIGNS WITH FLAT ON PLANETARY HUB
2 - FRONT ANNULUS THRUST WASHER
3 - TAB FACES FRONT
Fig. 221 Installing Front Annulus Snap-Ring
1 - SNAP-RING PLIERS
2 - FRONT ANNULUS SNAP-RING
Fig. 222 Installing Planetary Selective Snap-Ring
1 - SELECTIVE SNAP-RING
2 - SNAP-RING PLIERS
Fig. 223 Checking Planetary Geartrain End Play
1 - OUTPUT SHAFT
2 - REAR ANNULUS GEAR
3 - FEELER GAUGE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 117
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

ASSEMBLY
(1) Lubricate piston and guide seals (Fig. 235)
with petroleum jelly. Lubricate other servo parts with
MopartATF +4, type 9602, transmission fluid.
(2) Install new seal ring on servo piston.
(3) Assemble piston, plug, spring and new snap-
ring.
(4) Lubricate piston seal lip with petroleum jelly.
SHIFT MECHANISM
DESCRIPTION
The gear shift mechanism provides six shift posi-
tions which are:
²PARK (P)
²REVERSE (R)
²NEUTRAL (N)
²DRIVE (D)
²Manual SECOND (2)
²Manual LOW (1)
OPERATION
Manual LOW (1) range provides first gear only.
Overrun braking is also provided in this range. Man-
ual SECOND (2) range provides first and second gear
only.
DRIVE range provides first, second third and over-
drive fourth gear ranges. The shift into overdrive
fourth gear range occurs only after the transmission
has completed the shift into D third gear range. No
further movement of the shift mechanism is required
to complete the 3-4 shift.
The fourth gear upshift occurs automatically when
the overdrive selector switch is in the ON position.
No upshift to fourth gear will occur if any of the fol-
lowing are true:
²The transmission fluid temperature is below 10É
C (50É F) or above 121É C (250É F).
²The shift to third is not yet complete.
²Vehicle speed is too low for the 3-4 shift to occur.
²Battery temperature is below -5É C (23É F).
REMOVAL
(1) Remove any necessary console parts for access
to shift lever assembly and shifter cables. (Refer to
23 - BODY/INTERIOR/FLOOR CONSOLE -
REMOVAL)
(2) Shift transmission into PARK.
(3) Disconnect the transmission shift cable at shift
lever and shifter assembly bracket (Fig. 236).
(4) Disconnect the park lock cable from the shifter
BTSI lever and the shifter assembly bracket. (Fig.
237)
(5) Disconnect the transfer case shift cable from
the transfer case shift lever pin (Fig. 238), if
equipped.
(6) Remove the clip holding the transfer case shift
cable to the shifter assembly bracket, if equipped.
(7) Remove the transfer case shift cable from the
shifter assembly bracket, if equipped.
Fig. 234 Rear Servo Components
1 - SNAP-RING
2 - PISTON SEAL
3 - PISTON PLUG
4 - SPRING RETAINER
5 - SNAP-RING
6 - PISTON SPRING
7 - CUSHION SPRING
8 - PISTON
Fig. 235 Rear Servo Components
1 - SNAP-RING
2 - PISTON SEAL
3 - PISTON PLUG
4 - SPRING RETAINER
5 - SNAP-RING
6 - PISTON SPRING
7 - CUSHION SPRING
8 - PISTON
WJAUTOMATIC TRANSMISSION - 42RE 21 - 123
REAR SERVO (Continued)

A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
SPEED SENSOR
DESCRIPTION
The speed sensor (Fig. 240) is located in the over-
drive gear case. The sensor is positioned over the
park gear and monitors transmission output shaft
rotating speed.
OPERATION
Speed sensor signals are triggered by the park
gear lugs as they rotate past the sensor pickup face.
Input signals from the sensor are sent to the trans-
mission control module for processing. Signals from
this sensor are shared with the powertrain control
module.
THROTTLE VALVE CABLE
DESCRIPTION
Transmission throttle valve cable adjustment is
extremely important to proper operation. This adjust-
ment positions the throttle valve, which controls shift
speed, quality, and part-throttle downshift sensitivity.
If cable setting is too loose, early shifts and slip-
page between shifts may occur. If the setting is too
tight, shifts may be delayed and part throttle down-
shifts may be very sensitive.
The transmission throttle valve is operated by a
cam on the throttle lever. The throttle lever is oper-
ated by an adjustable cable (Fig. 241). The cable is
attached to an arm mounted on the throttle lever
shaft. A retaining clip at the engine-end of the cable
is removed to provide for cable adjustment. The
retaining clip is then installed back onto the throttle
valve cable to lock in the adjustment.
ADJUSTMENTS - TRANSMISSION THROTTLE
VALVE CABLE
A correctly adjusted throttle valve cable (Fig. 242)
will cause the throttle lever on the transmission to
move simultaneously with the throttle body lever
from the idle position. Proper adjustment will allow
Fig. 240 Transmission Output Speed Sensor
1 - TRANSMISSION OUTPUT SHAFT SPEED SENSOR
2 - SEAL
Fig. 241 Throttle Valve Cable
1 - THROTTLE VALVE CABLE
2 - THROTTLE VALVE LEVER
3 - THROTTLE BODY
21 - 126 AUTOMATIC TRANSMISSION - 42REWJ
SOLENOID (Continued)

TORQUE CONVERTER CLUTCH (TCC)
The torque converter clutch is hydraulically
applied and is released when fluid is vented from the
hydraulic circuit by the torque converter control
(TCC) solenoid on the valve body. The torque con-
verter clutch is controlled by the Powertrain Control
Module (PCM). The torque converter clutch engages
in fourth gear, and in third gear under various con-
ditions, such as when the O/D switch is OFF, when
the vehicle is cruising on a level surface after the
vehicle has warmed up. The torque converter clutch
will disengage momentarily when an increase in
engine load is sensed by the PCM, such as when the
vehicle begins to go uphill or the throttle pressure is
increased.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(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 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. 253). 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.
(9) Fill the transmission with the recommended
fluid.
Fig. 252 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
Fig. 253 Checking Torque Converter Seating -
Typical
1 - SCALE
2 - STRAIGHTEDGE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 133
TORQUE CONVERTER (Continued)

TORQUE CONVERTER
DRAINBACK VALVE
DESCRIPTION
The drainback valve is located in the transmission
cooler outlet (pressure) line.
OPERATION
The valve prevents fluid from draining from the
converter into the cooler and lines when the vehicle
is shut down for lengthy periods. Production valves
have a hose nipple at one end, while the opposite end
is threaded for a flare fitting. All valves have an
arrow (or similar mark) to indicate direction of flow
through the valve.
STANDARD PROCEDURE - TORQUE
CONVERTER DRAINBACK VALVE
The converter drainback check valve is located in
the cooler outlet (pressure) line near the radiator
tank. The valve prevents fluid drainback when the
vehicle is parked for lengthy periods. The valve check
ball is spring loaded and has an opening pressure of
approximately 2 psi.
The valve is serviced as an assembly; it is not
repairable. Do not clean the valve if restricted, or
contaminated by sludge, or debris. If the valve fails,
or if a transmission malfunction occurs that gener-
ates significant amounts of sludge and/or clutch par-
ticles and metal shavings, the valve must be
replaced.
The valve must be removed whenever the cooler
and lines are reverse flushed. The valve can be flow
tested when necessary. The procedure is exactly the
same as for flow testing a cooler.
If the valve is restricted, installed backwards, or in
the wrong line, it will cause an overheating condition
and possible transmission failure.
CAUTION: The drainback valve is a one-way flow
device. It must be properly oriented in terms of flow
direction for the cooler to function properly. The
valve must be installed in the pressure line. Other-
wise flow will be blocked and would cause an over-
heating condition and eventual transmission failure.
TRANSMISSION
TEMPERATURE SENSOR
DESCRIPTION
Transmission fluid temperature readings are sup-
plied to the transmission control module by the ther-
mistor (Fig. 254). The temperature readings are used
to control engagement of the fourth gear overdrive
clutch, the converter clutch, and governor pressure.
Normal resistance value for the thermistor at room
temperature is approximately 2000 ohms.
The thermistor is part of the governor pressure
sensor assembly and is immersed in transmission
fluid at all times.
OPERATION
The PCM prevents engagement of the converter
clutch and overdrive clutch, when fluid temperature
is below approximately 10ÉC (50ÉF).
If fluid temperature exceeds 126ÉC (260ÉF), the
PCM causes a 4-3 downshift and engage the con-
verter clutch. Engagement is according to the third
gear converter clutch engagement schedule.
The overdrive OFF lamp in the instrument panel
illuminates when the shift back to third occurs. The
transmission will not allow fourth gear operation
until fluid temperature decreases to approximately
110ÉC (230ÉF).
Fig. 254 Governor Pressure Sensor
1 - GOVERNOR BODY
2 - GOVERNOR PRESSURE SENSOR/TRANSMISSION FLUID
TEMPERATURE THERMISTOR
21 - 134 AUTOMATIC TRANSMISSION - 42REWJ