pack JEEP GRAND CHEROKEE 2003 WJ / 2.G Service Manual

CONDITION POSSIBLE CAUSES CORRECTION
OIL LEAKS. 1. Fluid Lines and Fittings
Loose/Leaks/Damaged.1. Tighten fittings. If leaks persist, replace fittings
and lines if necessary.
2. Fill Tube (where tube enters
case) Leaks/Damaged.2. Replace tube seal. Inspect tube for cracks in fill
tube.
3. Pressure Port Plug Loose
Loose/Damaged.3. Tighten to correct torque. Replace plug or
reseal if leak persists.
4. Pan Gasket Leaks. 4. Tighten pan screws (150 in. lbs.). If leaks
persist, replace gasket.
5. Valve Body Manual Lever Shaft
Seal Leaks/Worn.5. Replace shaft seal.
6. Rear Bearing Access Plate
Leaks.6. Replace gasket. Tighten screws.
7. Gasket Damaged or Bolts are
Loose.7. Replace bolts or gasket or tighten both.
8. Adapter/Extension Gasket
Damaged Leaks/Damaged.8. Replace gasket.
9. Park/Neutral Switch, or
Transmission Range Sensor
Leaks/Damaged.9. Replace switch and gasket.
10. Converter Housing Area Leaks. 10. Check for leaks at seal caused by worn seal
or burr on converter hub (cutting seal), worn
bushing, missing oil return, oil in front pump
housing or hole plugged. Check for leaks past
O-ring seal on pump or past pump-to-case bolts;
pump housing porous, oil coming out vent due to
overfill or leak past front band shaft access plug.
11. Pump Seal Leaks/Worn/
Damaged.11. Replace seal.
12. Torque Converter Weld
Leak/Cracked Hub.12. Replace converter.
13. Case Porosity Leaks. 13. Replace case.
NOISY OPERATION
IN FOURTH GEAR
ONLY1. Overdrive Clutch Discs, Plates
or Snap Rings Damaged.1. Remove unit and rebuild clutch pack.
2. Overdrive Piston or Planetary
Thrust Bearing Damaged.2. Remove and disassemble unit. Replace either
thrust bearing if damaged.
3. Output Shaft Bearings
Scored/Damaged.3. Remove and disassemble unit. Replace either
bearing if damaged.
4. Planetary Gears Worn/Chipped. 4. Remove and overhaul overdrive unit.
5. Overdrive Unit Overrunning
Clutch Rollers Worn/Scored.5. Remove and overhaul overdrive unit.
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
mission case and valve body can be repaired by the
use of Heli-CoilsŸ, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-CoilŸ tap, or
equivalent, and installing a Heli-CoilŸ insert, orequivalent, into the hole. This brings the hole back to
its original thread size.
Heli-CoilŸ, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
21 - 26 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

SPECIFICATIONS
TRANSMISSION
GENERAL
Component Metric Inch
Planetary end play 0.127-1.22
mm0.005-0.048
in.
Input shaft end play 0.56-2.31
mm0.022-0.091
in.
Clutch pack clearance/
Front.1.70-
3.40mm0.067-0.134
in.
Clutch pack clearance/
Rear.0.559-0.914
mm0.022-0.036
in.
Front clutch 4 discs
Rear clutch 4 discs
Overdrive clutch 3 discs
Component Metric Inch
Direct clutch 6 discs
42RE Band adjustment
from 72 in. lbs.
Front band Back off 3 turns
Rear band Back off 4 turns
Recommended fluid MoparTATF +4, type 9602
GEAR RATIOS
1ST GEAR 2.74:1
2ND GEAR 1.54:1
3RD GEAR 1.0:1
4TH GEAR 0.69:1
REVERSE 2.21:1
THRUST WASHER/SPACER/SNAP-RING DIMENSIONS
Component Metric Inch
Front clutch thrust washer (reaction shaft
support hub)1.55 mm 0.061 in.
Rear clutch thrust washer (clutch retainer) 1.55 mm 0.061 in.
Intermediate shaft thrust plate (shaft hub pilot) Select fit to set end play
Output shaft thrust washer (rear clutch hub) 1.5-1.6 mm 0.060-0.063 in.
Rear clutch pack snap-ring 1.5 mm 0.060 in.
1.95 mm 0.076 in.
2.45 mm 0.098 in.
Planetary geartrain snap-ring (at front of output shaft) Select fit (three thicknesses avalible)
Overdrive piston thrust plate Thrust plate and
spacer are select fit.
Refer to size charts
and selection
procedures in
Overdrive Unit D&A
procedures Intermiediate shaft spacer
WJAUTOMATIC TRANSMISSION - 42RE 21 - 55
AUTOMATIC TRANSMISSION - 42RE (Continued)

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)

OVERDRIVE CLUTCH
DESCRIPTION
The overdrive clutch (Fig. 125) is composed of the
pressure plate, clutch plates, holding discs, overdrive
piston retainer, piston, piston spacer, and snap-rings.
The overdrive clutch is the forwardmost component
in the transmission overdrive unit and is considered
a holding component. The overdrive piston retainer,
piston, and piston spacer are located on the rear of
the main transmission case.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
OPERATION
To apply the clutch, pressure is applied between
the piston retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through passages at the lower rear portion of
the valve body area. With pressure applied between
the piston retainer and piston, the piston moves
away from the piston retainer and compresses the
clutch pack. This action applies the clutch pack,
allowing torque to flow through the intermediate
shaft into the overdrive planetary gear set. The over-
drive clutch discs are attached to the overdrive clutch
hub while the overdrive clutch plates, reaction plate,
and pressure plate are lugged to the overdrive hous-
ing. This allows the intermediate shaft to transferthe engine torque to the planetary gear and overrun-
ning clutch. This drives the planetary gear inside the
annulus, which is attached to the overdrive clutch
drum and output shaft, creating the desired gear
ratio. The waved snap-ring is used to cushion the
application of the clutch pack.
OVERDRIVE OFF SWITCH
DESCRIPTION
The overdrive OFF (control) switch is located in
the shifter handle. The switch is a momentary con-
tact device that signals the PCM to toggle current
status of the overdrive function.
OPERATION
At key-on, fourth gear operation is allowed. Press-
ing the switch once causes the overdrive OFF mode
to be entered and the overdrive OFF switch lamp to
be illuminated. Pressing the switch a second time
causes normal overdrive operation to be restored and
the overdrive lamp to be turned off. The overdrive
OFF mode defaults to ON after the ignition switch is
cycled OFF and ON. The normal position for the con-
trol switch is the ON position. The switch must be in
this position to energize the solenoid and allow
upshifts to fourth gear. The control switch indicator
light illuminates only when the overdrive switch is
turned to the OFF position, or when illuminated by
the powertrain control module.
Fig. 125 Overdrive Clutch
1 - REACTION PLATE 2 - PRESSURE PLATE
21 - 86 AUTOMATIC TRANSMISSION - 42REWJ

OVERDRIVE CLUTCH PACK
(1) Remove overdrive clutch pack wire retaining
ring (Fig. 132).
(2) Remove overdrive clutch pack (Fig. 133).
NOTE: The 42RE transmission has three clutch
discs and two clutch plates.
(3) Note position of clutch pack components for
assembly reference (Fig. 134).
Fig. 131 Overdrive Piston Removal
1 - PISTON RETAINER
2 - OVERDRIVE PISTON
Fig. 132 Removing Overdrive Clutch Pack Retaining
Ring
1 - OVERDRIVE CLUTCH PACK RETAINING RING
Fig. 133 Overdrive Clutch Pack Removal
1 - OVERDRIVE CLUTCH PACK
Fig. 134 42RE Overdrive Clutch Component
Position
1 - PRESSURE PLATE (TO FRONT)
2 - OVERDRIVE CLUTCH PACK
3 - CLUTCH DISC (3)
4 - CLUTCH PLATE (2)
5 - REACTION PLATE (TO REAR)
WJAUTOMATIC TRANSMISSION - 42RE 21 - 89
OVERDRIVE UNIT (Continued)

DIRECT CLUTCH, HUB AND SPRING
WARNING: THE NEXT STEP IN DISASSEMBLY
INVOLVES COMPRESSING THE DIRECT CLUTCH
SPRING. IT IS EXTREMELY IMPORTANT THAT
PROPER EQUIPMENT BE USED TO COMPRESS
THE SPRING AS SPRING FORCE IS APPROXI-
MATELY 830 POUNDS. USE SPRING COMPRESSOR
TOOL 6227-1 AND A HYDRAULIC SHOP PRESS
WITH A MINIMUM RAM TRAVEL OF 5-6 INCHES.
THE PRESS MUST ALSO HAVE A BED THAT CAN
BE ADJUSTED UP OR DOWN AS REQUIRED.
RELEASE CLUTCH SPRING TENSION SLOWLY AND
COMPLETELY TO AVOID PERSONAL INJURY.(1) Mount geartrain assembly in shop press (Fig.
142).
(2) Position Compressor Tool 6227-1 on clutch hub
(Fig. 142). Support output shaft flange with steel
press plates as shown and center assembly under
press ram.
(3) Apply press pressure slowly. Compress hub and
spring far enough to expose clutch hub retaining ring
and relieve spring pressure on clutch pack snap-ring
(Fig. 142).
(4) Remove direct clutch pack snap-ring (Fig. 143).
(5) Remove direct clutch hub retaining ring (Fig.
144).
(6) Release press load slowly and completely (Fig.
145).
(7) Remove Special Tool 6227-1. Then remove
clutch pack from hub (Fig. 145).
GEARTRAIN
(1) Remove direct clutch hub and spring (Fig. 146).
Fig. 140 Removing Gear Case From Geartrain
Assembly
1 - GEARTRAIN ASSEMBLY
2 - GEAR CASE
Fig. 141 Rear Bearing Removal
1 - OUTPUT SHAFT
2 - REAR BEARING
3 - SNAP-RING
Fig. 142 Geartrain Mounted In Shop Press
1 - PRESS RAM
2 - SPECIAL TOOL C-3995-A (OR SIMILAR TOOL)
3 - CLUTCH HUB
4 - PLATES
5 - PRESS BED
6 - SPECIAL TOOL 6227-1
WJAUTOMATIC TRANSMISSION - 42RE 21 - 91
OVERDRIVE UNIT (Continued)

(2) Remove sun gear and spring plate. Then
remove planetary thrust bearing and planetary gear
(Fig. 147).
(3) Remove overrunning clutch assembly with
expanding type snap-ring pliers (Fig. 148). Insert pli-
ers into clutch hub. Expand pliers to grip hub splines
and remove clutch with counterclockwise, twisting
motion.
(4) Remove thrust bearing from overrunning
clutch hub.
Fig. 143 Direct Clutch Pack Snap-Ring Removal
1 - CLUTCH HUB
2 - SPECIAL TOOL 6227-1
3 - DIRECT CLUTCH PACK SNAP-RING
4 - PRESS PLATES
5 - CLUTCH DRUM
Fig. 144 Direct Clutch Hub Retaining Ring Removal
1 - SPECIAL TOOL 6227-1
2 - CLUTCH HUB RETAINING RING
3 - PRESS BED
4 - PRESS PLATES
Fig. 145 Direct Clutch Pack Removal
1 - SPECIAL TOOL 6227-1
2 - DIRECT CLUTCH HUB
3 - DIRECT CLUTCH PACK
Fig. 146 Direct Clutch Hub And Spring Removal
1 - DIRECT CLUTCH SPRING
2 - DIRECT CLUTCH HUB
21 - 92 AUTOMATIC TRANSMISSION - 42REWJ
OVERDRIVE UNIT (Continued)

(15) Mount assembled output shaft, annulus gear,
and clutch drum in shop press. Direct clutch spring,
hub and clutch pack are easier to install with assem-
bly mounted in press.
(16) Align splines in hubs of planetary gear and
overrunning clutch with Alignment tool 6227-2 (Fig.
165). Insert tool through sun gear and into splines of
both hubs. Be sure alignment tool is fully seated
before proceeding.
(17) Install direct clutch spring (Fig. 166). Be sure
spring is properly seated on spring plate.
NOTE: The 42RE transmission has 6 direct clutch
discs and 5 clutch plates.
(18) Assemble and install direct clutch pack on
hub as follows:
(a) Assemble clutch pack components (Fig. 167).
(b) Install direct clutch reaction plate on clutch
hub first. Note that one side of reaction plate is
counterbored. Be sure this side faces rearward.
Splines at rear of hub are raised slightly. Counter-
bore in plate fits over raised splines. Plate should
be flush with this end of hub (Fig. 168).
(c) Install first clutch disc followed by a steel
plate until all discs and plates have been installed.
(d) Install pressure plate. This is last clutch
pack item to be installed. Be sure plate is installed
with shoulder side facing upward (Fig. 169).
(19) Install clutch hub and clutch pack on direct
clutch spring (Fig. 170). Be sure hub is started on
sun gear splines before proceeding.
Fig. 164 Sun Gear Installation
1 - SUN GEAR AND SPRING PLATE ASSEMBLY
Fig. 165 Alignment Tool Installation
1 - SPECIAL TOOL 6227-2
2 - PRESS PLATES
3 - ASSEMBLED DRUM AND ANNULUS GEAR
4 - SUN GEAR
Fig. 166 Direct Clutch Spring Installation
1 - SPECIAL TOOL 6227-2
2 - DIRECT CLUTCH SPRING
3 - CLUTCH HUB
4 - PRESS PLATES
21 - 98 AUTOMATIC TRANSMISSION - 42REWJ
OVERDRIVE UNIT (Continued)

Fig. 167 42RE Direct Clutch Pack Components
1 - REACTION PLATE 2 - PRESSURE PLATE
Fig. 168 Correct Position Of Direct Clutch Reaction
Plate
1 - REACTION PLATE COUNTERBORE
2 - DIRECT CLUTCH REACTION PLATE (FLUSH WITH END OF
HUB)
3 - CLUTCH HUB
Fig. 169 Correct Position Of Direct Clutch Pressure
Plate
1 - DIRECT CLUTCH PRESSURE PLATE
2 - CLUTCH PACK
3 - BE SURE SHOULDER SIDE OF PLATE FACES UPWARD
WJAUTOMATIC TRANSMISSION - 42RE 21 - 99
OVERDRIVE UNIT (Continued)

WARNING: THE NEXT STEP IN GEARTRAIN
ASSEMBLY INVOLVES COMPRESSING THE DIRECT
CLUTCH HUB AND SPRING. IT IS EXTREMELY
IMPORTANT THAT PROPER EQUIPMENT BE USED
TO COMPRESS THE SPRING AS SPRING FORCE IS
APPROXIMATELY 830 POUNDS. USE COMPRES-
SOR TOOL C-6227-1 AND A HYDRAULIC-TYPE
SHOP PRESS WITH A MINIMUM RAM TRAVEL OF 6
INCHES. THE PRESS MUST ALSO HAVE A BED
THAT CAN BE ADJUSTED UP OR DOWN AS
REQUIRED. RELEASE CLUTCH SPRING TENSION
SLOWLY AND COMPLETELY TO AVOID PERSONAL
INJURY.
(20) Position Compressor Tool 6227-1 on clutch
hub.
(21) Compress clutch hub and spring just enough
to place tension on hub and hold it in place.
(22) Slowly compress clutch hub and spring. Com-
press spring and hub only enough to expose ring
grooves for clutch pack snap ring and clutch hub
retaining ring.
(23) Realign clutch pack on hub and seat clutch
discs and plates in clutch drum.
(24) Install direct clutch pack snap-ring (Fig. 171).
Be very sure snap-ring is fully seated in clutch drum
ring groove.
(25) Install clutch hub retaining ring (Fig. 172). Be
very sure retaining ring is fully seated in sun gear
ring groove.
(26) Slowly release press ram, remove compressor
tools and remove geartrain assembly.
GEAR CASE
(1) Position park pawl and spring in case and
install park pawl shaft. Verify that end of spring
with 90É bend is hooked to pawl and straight end of
spring is seated against case.
(2) Install pawl shaft retaining bolt. Tighten bolt
to 27 N´m (20 ft. lbs.) torque.
(3) Install park lock reaction plug. Note that plug
has locating pin at rear (Fig. 173). Be sure pin is
seated in hole in case before installing snap-ring.
(4) Install reaction plug snap-ring (Fig. 174). Com-
press snap ring only enough for installation; do not
distort it.
Fig. 170 Direct Clutch
1 - CLUTCH HUB
2 - DIRECT CLUTCH PACK
3 - CLUTCH DRUM
Fig. 171 Direct Clutch Pack Snap-Ring Installation
1 - SPECIAL TOOL 6227-1
2 - DIRECT CLUTCH PACK SNAP-RING
Fig. 172 Clutch Hub Retaining Ring Installation
1 - SPECIAL TOOL 6227-1
2 - CLUTCH HUB RETAINING RING
21 - 100 AUTOMATIC TRANSMISSION - 42REWJ
OVERDRIVE UNIT (Continued)