JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual

(7) While holding pan level, lower pan and gasket
away from transmission.
(8) Pour remaining fluid in pan into drain pan.
(9) Remove screws holding filter to valve body
(Fig. 90).
(10) Separate filter from valve body and pour fluid
in filter into drain pan.
(11) Dispose of used trans fluid and filter properly.
INSTALLATION
(1) Position a new transmission oil filter onto the
valve body.
(2) Install the screws to hold the filter to the valve
body. Tighten the screws to 4 N´m (35 in.lbs.).
(3) Clean the gasket surfaces of the transmission
oil pan and transmission pan rail.NOTE: The transmission pan oil gasket is reusable.
Inspect the sealing surfaces of the gasket. If the
sealing ribs on both surfaces appear to be in good
condition, clean the gasket of any foreign material
and reinstall.
(4) Position the oil pan gasket onto the oil pan.
(5) Position the oil pan and gasket onto the trans-
mission and install several bolts to hold the pan and
gasket to the transmission.
(6) Install the remainder of the oil pan bolts.
Tighten the bolts to 13.6 N´m (125 in.lbs.).
(7) Lower vehicle and fill transmission. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC/
FLUID - STANDARD PROCEDURE)
STANDARD PROCEDURE - TRANSMISSION
FILL
To avoid overfilling transmission after a fluid
change or overhaul, perform the following procedure:
(1) Remove dipstick and insert clean funnel in
transmission fill tube.
(2) Add following initial quantity of MopartAT F
+4, type 9602, to transmission:
(a) If only fluid and filter were changed, add3
pints (1-1/2 quarts)of ATF +4 to transmission.
(b) If transmission was completely overhauled,
torque converter was replaced or drained, and
cooler was flushed, add12 pints (6 quarts)of ATF
+4 to transmission.
(3) Apply parking brakes.
(4)
Start and run engine at normal curb idle speed.
(5) Apply service brakes, shift transmission
through all gear ranges then back to NEUTRAL, set
parking brake, and leave engine running at curb idle
speed.
(6) Remove funnel, insert dipstick and check fluid
level. If level is low,add fluid to bring level to
MIN mark on dipstick.Check to see if the oil level
is equal on both sides of the dipstick. If one side is
noticably higher than the other, the dipstick has
picked up some oil from the dipstick tube. Allow the
oil to drain down the dipstick tube and re-check.
(7) Drive vehicle until transmission fluid is at nor-
mal operating temperature.
(8) With the engine running at curb idle speed, the
gear selector in NEUTRAL, and the parking brake
applied, check the transmission fluid level.
CAUTION: Do not overfill transmission, fluid foam-
ing and shifting problems can result.
(9) Add fluid to bring level up to MAX arrow
mark.
When fluid level is correct, shut engine off, release
park brake, remove funnel, and install dipstick in fill
tube.
Fig. 89 Transmission Pan
1 - TRANSMISSION
2 - GASKET
3-PAN
Fig. 90 Transmission Filter
1 - TRANSMISSION
2 - FILTER
21 - 72 AUTOMATIC TRANSMISSION - 42REWJ
FLUID AND FILTER (Continued)

FRONT CLUTCH
DESCRIPTION
The front clutch assembly (Fig. 91) is composed of
the front clutch retainer, pressure plate, clutch
plates, driving discs, piston, piston return spring,
return spring retainer, and snap-rings. The frontclutch is the forward-most component in the trans-
mission geartrain and is directly behind the oil pump
and is considered a driving component.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
Fig. 91 Front Clutch Components
1 - SNAP-RING (WAVE) 7 - SEAL
2 - REACTION PLATE 8 - PISTON
3 - CLUTCH DISC 9 - SPRING
4 - CLUTCH PLATE 10 - SNAP-RING
5 - SEAL 11 - SPRING RETAINER
6 - CLUTCH RETAINER
WJAUTOMATIC TRANSMISSION - 42RE 21 - 73

OPERATION
To apply the clutch, pressure is applied between
the clutch retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through the hub of the reaction shaft support.
With pressure applied between the clutch retainer
and piston, the piston moves away from the clutch
retainer and compresses the clutch pack. This action
applies the clutch pack, allowing torque to flow
through the input shaft into the driving discs, and
into the clutch plates and pressure plate that are
lugged to the clutch retainer. The waved snap-ring is
used to cushion the application of the clutch pack.
When pressure is released from the piston, the
spring returns the piston to its fully released position
and disengages the clutch. The release spring also
helps to cushion the application of the clutch assem-
bly. When the clutch is in the process of being
released by the release spring, fluid flows through a
vent and one-way ball-check-valve located in the
clutch retainer. The check-valve is needed to elimi-
nate the possibility of plate drag caused by centrifu-
gal force acting on the residual fluid trapped in the
clutch piston retainer.
DISASSEMBLY
(1) Remove waved snap-ring and remove pressure
plate, clutch plates and clutch discs (Fig. 92).
(2) Compress clutch piston spring with Compressor
Tool C-3575-A (Fig. 93). Be sure legs of tool are
seated squarely on spring retainer before compress-
ing spring.
(3) Remove retainer snap-ring and remove com-
pressor tool.
(4) Remove spring retainer and clutch spring. Note
position of retainer on spring for assembly reference.
(5) Remove clutch piston from clutch retainer.
Remove piston by rotating it up and out of retainer.
(6) Remove seals from clutch retainer piston bore
and clutch retainer hub. Discard both seals as they
are not reusable.
INSPECTION
Inspect the front clutch components. Replace the
clutch discs if warped, worn, scored, burned or
charred, or if the facing is flaking off. Replace the
steel plates if heavily scored, warped, or broken. Be
sure the driving lugs on the plates are in good con-
dition. The lugs must not be bent, cracked or dam-
aged in any way.
Replace the clutch spring and spring retainer if
either is distorted, warped or broken.Check the lug grooves in the clutch retainer. The
steel plates should slide freely in the slots. Replace
the retainer if the grooves are worn or damaged.
Check action of the check ball in the retainer (Fig.
94). The ball must move freely and not stick.
NOTE: Inspect the clutch retainer bushings care-
fully (Fig. 95). The retainer bushings are NOT ser-
viceable. It will be necessary to replace the retainer
if either bushing is scored, or worn.
Inspect the piston and retainer seal surfaces for
nicks or scratches. Minor scratches can be removed
with crocus cloth. However, replace the piston and/or
retainer if the seal surfaces are seriously scored.
ASSEMBLY
NOTE: The 42RE transmission uses four plates and
discs for the front clutch.
(1) Soak clutch discs in transmission fluid while
assembling other clutch parts.
(2) Install new seals in the clutch retainer lower
groove and on outer diameter of the retainer hub. Be
sure lip of each seal faces interior of clutch retainer.
(3) Lubricate lips of the retainer seals with liberal
quantity of MopartDoor Ease. Then lubricate
retainer hub, bore and piston with light coat of trans-
mission fluid.
(4) Install clutch piston in retainer (Fig. 96). Use
twisting motion to seat piston in bottom of retainer.
CAUTION: Never push the clutch piston straight in.
This will fold the seals over causing leakage and
clutch slip.
(5) Position spring in clutch piston (Fig. 97).
(6) Position spring retainer on top of piston spring.
Make sure retainer is properly installed (Fig. 92).
(7) Compress piston spring and retainer with Com-
pressor Tool C-3575-A (Fig. 93). Then install new
snap-ring to secure spring retainer and spring.
(8) Install clutch plates and discs (Fig. 92). Install
steel plate then disc until all plates and discs are
installed. The front clutch uses 4 clutch discs and
plates in a 42RE transmission.
(9) Install pressure plate and waved snap-ring
(Fig. 92).
Clearance should be 1.70 to 3.40 mm (0.067 to
0.134 in.). If clearance is incorrect, clutch discs,
plates, pressure plates and snap-ring may have to be
changed.
21 - 74 AUTOMATIC TRANSMISSION - 42REWJ
FRONT CLUTCH (Continued)

Fig. 92 42RE Front Clutch Components
1 - SNAP-RING (WAVE) 7 - SEAL
2 - REACTION PLATE 8 - PISTON
3 - CLUTCH DISC 9 - SPRING
4 - CLUTCH PLATE 10 - SNAP-RING
5 - SEAL 11 - SPRING RETAINER
6 - CLUTCH RETAINER
WJAUTOMATIC TRANSMISSION - 42RE 21 - 75
FRONT CLUTCH (Continued)

Fig. 93 Compressing Front Clutch Piston Spring
1 - FRONT CLUTCH SPRING
2 - COMPRESSOR TOOL C-3575-A
3 - RETAINER SNAP-RING
4 - SPRING RETAINER
Fig. 94 Front Clutch Piston Retainer Check Ball
Location
1 - RETAINER CHECK BALL
Fig. 95 Retainer Bushing Location/Inspection
1 - FRONT CLUTCH RETAINER BUSHINGS (NON-
SERVICEABLE)
Fig. 96 Front Clutch Piston Installation
1 - CLUTCH PISTON
2 - FRONT CLUTCH RETAINER
Fig. 97 Clutch Piston Spring Installation
1 - RETAINER
2 - CLUTCH SPRING
3 - PISTON
21 - 76 AUTOMATIC TRANSMISSION - 42REWJ
FRONT CLUTCH (Continued)

FRONT SERVO
DESCRIPTION
The kickdown servo (Fig. 98) consists of a two-land
piston with an inner piston, a piston rod and guide,
and a return spring. The dual-land piston uses seal
rings on its outer diameters and an O-ring for the
inner piston.
OPERATION
The application of the piston is accomplished by
applying pressure between the two lands of the pis-
ton. The pressure acts against the larger lower land
to push the piston downward, allowing the piston rod
to extend though its guide against the apply lever.
Release of the servo at the 2-3 upshift is accom-
plished by a combination of spring and line pressure,
acting on the bottom of the larger land of the piston.
The small piston is used to cushion the application of
the band by bleeding oil through a small orifice in
the larger piston. The release timing of the kickdown
servo is very important to obtain a smooth but firm
shift. The release has to be very quick, just as the
front clutch application is taking place. Otherwise,
engine runaway or a shift hesitation will occur. To
accomplish this, the band retains its holding capacity
until the front clutch is applied, giving a small
amount of overlap between them.
DISASSEMBLY
(1) Remove seal ring from rod guide (Fig. 99).(2) Remove small snap-ring from servo piston rod.
Then remove piston rod, spring and washer from pis-
ton.
(3) Remove and discard servo component o-ring
and seal rings.
CLEANING
Clean the servo piston components (Fig. 100) with
solvent and dry them with compressed air.
INSPECTION
Inspect the servo components (Fig. 101). Replace
the springs if collapsed, distorted or broken. Replace
the guide, rod and piston if cracked, bent, or worn.
Discard the servo snap-ring if distorted or warped.
Check the servo piston bore for wear. If the bore is
severely scored, or damaged, it will be necessary to
replace the case.
Replace any servo component if doubt exists about
condition. Do not reuse suspect parts.
ASSEMBLY
Clean and inspect front servo components.
(1) Lubricate new o-ring and seal rings with petro-
leum jelly and install them on piston, guide and rod.
(2) Install rod in piston. Install spring and washer
on rod. Compress spring and install snap-ring (Fig.
102).
Fig. 98 Front Servo
1 - VENT
2 -PISTON ROD
3 - PISTON
4 - SPRING
5 - RELEASE PRESSURE
6 - APPLY PRESSURE
Fig. 99 Front Servo
1 - PISTON RINGS
2 - O-RING
3 - SNAP-RING
4 - SEAL RING
5 - PISTON ROD GUIDE
6 - SNAP-RING
7 - SERVO SPRING
8 - PISTON ROD
9 - SERVO PISTON
WJAUTOMATIC TRANSMISSION - 42RE 21 - 77

GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE
(1) The floor shifter lever and gate positions
should be in alignment with all transmission PARK,
NEUTRAL, and gear detent positions.
(2) Engine starts must be possible with floor shift
lever in PARK or NEUTRAL gate positions only.
Engine starts must not be possible in any other gear
position.
(3) With floor shift lever handle push-button not
depressed and lever in:
(a) PARK position - Apply forward force on cen-
ter of handle and remove pressure. Engine starts
must be possible.
(b) PARK position - Apply rearward force on cen-
ter of handle and remove pressure. Engine starts
must be possible.
(c) NEUTRAL position - Normal position. Engine
starts must be possible.
(d) NEUTRAL position - Engine running and
brakes applied, apply forward force on center of
shift handle. Transmission shall not be able to shift
from NEUTRAL to REVERSE.
REMOVAL
(1) Shift transmission into PARK.
(2) Raise vehicle.
Fig. 100 Front Servo Piston
1 - PISTON RINGS
2 - O-RING
3 - SNAP-RING
4 - SEAL RING
5 - PISTON ROD GUIDE
6 - SNAP-RING
7 - SERVO SPRING
8 - PISTON ROD
9 - SERVO PISTON
Fig. 101 Front Servo Piston
1 - PISTON RINGS
2 - O-RING
3 - SNAP-RING
4 - SEAL RING
5 - PISTON ROD GUIDE
6 - SNAP-RING
7 - SERVO SPRING
8 - PISTON ROD
9 - SERVO PISTON
Fig. 102 Front Servo
1 - PISTON RINGS
2 - O-RING
3 - SNAP-RING
4 - SEAL RING
5 - PISTON ROD GUIDE
6 - SNAP-RING
7 - SERVO SPRING
8 - PISTON ROD
9 - SERVO PISTON
21 - 78 AUTOMATIC TRANSMISSION - 42REWJ
FRONT SERVO (Continued)

(3) Remove the shift cable eyelet from the trans-
mission manual shift lever (Fig. 103).
(4) Remove shift cable from the cable support
bracket.
(5) Lower vehicle.
(6) Remove necessary console parts for access to
shift lever assembly and shift cable. (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - REMOVAL)
(7) Disconnect cable at shift lever and shifter
assembly bracket (Fig. 104).
(8) Remove the nuts holding the shift cable seal
plate to the floor pan (Fig. 105).
(9) Pull cable through floor panel opening.(10) Remove shift cable from vehicle.
INSTALLATION
(1) Route cable through hole in floor pan.
(2) Install seal plate to studs in floor pan.
(3) Install nuts to hold seal plate to floor pan.
Tighten nuts to 7 N´m (65 in.lbs.).
(4) Install the shift cable to the shifter assembly
bracket. Push cable into the bracket until secure.
(5) Place the floor shifter lever in PARK position.
(6) Loosen the adjustment screw on the shift cable.
(7) Snap the shift cable onto the shift lever pin.
(8) Raise the vehicle.
(9) Install the shift cable to the shift cable support
bracket.
(10) Shift the transmission into PARK. PARK is
the rearmost detent position on the transmission
manual shift lever.
(11) Snap the shift cable onto the transmission
manual shift lever.
(12) Lower vehicle.
(13) Verify that the shift lever is in the PARK posi-
tion.
(14) Tighten the adjustment screw to 7 N´m (65
in.lbs.).
(15) Verify correct shifter operation.
(16) Install any console parts removed for access to
shift lever assembly and shift cable. (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - INSTALLA-
TION)
ADJUSTMENTS - GEARSHIFT CABLE
Check adjustment by starting the engine in PARK
and NEUTRAL. Adjustment is CORRECT if the
engine starts only in these positions. Adjustment is
Fig. 103 Remove Shift Cable From Transmission
1 - SHIFT CABLE
2 - MANUAL LEVER
3 - MANUAL LEVER
Fig. 104 Transmission Shift Cable at Shifter
1 - SHIFT LEVER PIN
2 - ADJUSTMENT SCREW
3 - SHIFT CABLE
4 - SHIFTER ASSEMBLY BRACKET
Fig. 105 Shift Cables at Floor Pan
1 - SEAL PLATES
2 - TRANSMISSION SHIFT CABLE
3 - TRANSFER CASE SHIFT CABLE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 79
GEARSHIFT CABLE (Continued)

INCORRECT if the engine starts in one but not both
positions. If the engine starts in any position other
than PARK or NEUTRAL, or if the engine will not
start at all, the park/neutral position switch or TRS
may be faulty.
(1) Shift transmission into PARK.
(2) Remove floor console as necessary for access to
the shift cable adjustment. (Refer to 23 - BODY/IN-
TERIOR/FLOOR CONSOLE - REMOVAL)
(3) Loosen the shift cable adjustment screw (Fig.
106).
(4) Raise vehicle.
(5) Unsnap cable eyelet from transmission shift
lever (Fig. 107).
(6) Verify transmission shift lever is in PARK
detent by moving lever fully rearward. Last rearward
detent is PARK position.
(7) Verify positive engagement of transmission
park lock by attempting to rotate propeller shaft.
Shaft will not rotate when park lock is engaged.
(8) Snap cable eyelet onto transmission shift lever.
(9) Lower vehicle
(10) Tighten the shift cable adjustment screw to 7
N´m (65 in.lbs.).
(11) Verify correct operation.
(12) Install any floor console components removed
for access. (Refer to 23 - BODY/INTERIOR/FLOOR
CONSOLE - INSTALLATION)
OIL PUMP
DESCRIPTION
The oil pump (Fig. 108) is located in the pump
housing inside the bell housing of the transmission
case. The oil pump consists of an inner and outer
gear (Fig. 109), a housing, and a cover that also
serves as the reaction shaft support.
OPERATION
As the torque converter rotates, the converter hub
rotates the inner and outer gears. As the gears
rotate, the clearance between the gear teeth
increases in the crescent area, and creates a suction
at the inlet side of the pump. This suction draws
fluid through the pump inlet from the oil pan. As the
clearance between the gear teeth in the crescent area
decreases, it forces pressurized fluid into the pump
outlet and to the valve body.
Fig. 106 Shift Cable at the Shifter
1 - SHIFT LEVER PIN
2 - ADJUSTMENT SCREW
3 - SHIFT CABLE
4 - SHIFTER ASSEMBLY BRACKET
Fig. 107 Shift Cable at Transmission
1 - TRANSMISSION SHIFTER CABLE
2 - THROTTLE VALVE CABLE
3 - TRANSFER CASE SHIFTER CABLE
4 - TRANSFER CASE SHIFTER CABLE BRACKET RETAINING
BOLT(S)
5 - THROTTLE VALVE CABLE BRACKET RETAINING BOLT
6 - ELECTRICAL CONNECTORS
7 - TRANSMISSION FLUID LINES
21 - 80 AUTOMATIC TRANSMISSION - 42REWJ
GEARSHIFT CABLE (Continued)

STANDARD PROCEDURE - OIL PUMP VOLUME
CHECK
Measuring the oil pump output volume will deter-
mine if sufficient oil flow to the transmission oil
cooler exists, and whether or not an internal trans-
mission failure is present.
Verify that the transmission fluid is at the proper
level. Refer to the Fluid Level Check procedure in
this section. If necessary, fill the transmission to the
proper level with MopartATF +4, type 9602, Auto-
matic Transmission Fluid.
(1) Disconnect theTo coolerline at the cooler
inlet and place a collecting container under the dis-
connected line.
CAUTION: With the fluid set at the proper level,
fluid collection should not exceed (1) quart or inter-
nal damage to the transmission may occur.
(2) Run the engineat curb idle speed, with the
shift selector in neutral.(3) If one quart of transmission fluid is collected in
the container in 20 seconds or less, oil pump flow vol-
ume is within acceptable limits. If fluid flow is inter-
mittent, or it takes more than 20 seconds to collect
one quart of fluid, refer to the Hydraulic Pressure
tests in this section for further diagnosis.
(4) Re-connect theTo coolerline to the transmis-
sion cooler inlet.
(5) Refill the transmission to proper level.
DISASSEMBLY
(1) Remove seal ring from housing and reaction
shaft support (Fig. 110).
(2) Mark pump housing and support assembly for
alignment reference.
(3) Remove bolts attaching pump body to support
(Fig. 111).
(4) Separate support from pump housing (Fig.
112).
(5) Remove inner and outer gears from reaction
shaft support (Fig. 113).
Fig. 108 Oil Pump and Reaction Shaft Support
1 - REACTION SHAFT SUPPORT
2 - PUMP
Fig. 109 Pump Gear Removal
1 - REACTION SHAFT SUPPORT
2 - INNER GEAR
3 - OUTER GEAR
Fig. 110 Removing Pump Seal Ring
1 - PUMP HOUSING SEAL RING
Fig. 111 Pump Support Bolts
1 - REACTION SHAFT SUPPORT
2 - PUMP
WJAUTOMATIC TRANSMISSION - 42RE 21 - 81
OIL PUMP (Continued)