2003 JEEP GRAND CHEROKEE spec

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

(6) If pump seal was not removed during transmis-
sion disassembly, remove seal with punch and ham-
mer.
(7) Remove front clutch thrust washer from sup-
port hub (Fig. 114).
OIL PUMP BUSHING REPLACEMENT
(1) Remove pump bushing with Tool Handle
C-4171 and Bushing Remover SP-3551 from Tool Set
C-3887-J (Fig. 115).
(2) Install new pump bushing with Tool Handle
C-4171 and Bushing Installer SP-5117 (Fig. 115).
Bushing should be flush with pump housing bore.
(3) Stake new pump bushing in two places with
blunt punch (Fig. 116). Remove burrs from stake
points with knife blade afterward.
REACTION SHAFT SUPPORT BUSHING REMOVAL
(1) Assemble Bushing Remover Tools SP-1191,
3633 and 5324 (Fig. 117). Do not clamp any part of
reaction shaft or support in vise.
(2) Hold Cup Tool SP-3633 firmly against reaction
shaft and thread remover SP-5324 into bushing as
far as possible by hand. Then thread remover tool 3-4
additional turns into bushing with a wrench.(3) Turn remover tool hex nut down against
remover cup to pull bushing from shaft. Clean all
chips from shaft after bushing removal.
Fig. 112 Separating Pump Housing From Reaction
Shaft Support
1 - REACTION SHAFT SUPPORT
2 - PUMP HOUSING
Fig. 113 Pump Gear Removal
1 - REACTION SHAFT SUPPORT
2 - INNER GEAR
3 - OUTER GEAR
Fig. 114 Support Hub Thrust Washer
1 - BUSHING
2 - REACTION SHAFT SUPPORT
3 - THRUST WASHER
4 - HUB
Fig. 115 Removing Oil Pump Bushing
1 - SPECIAL TOOL C-4171
2 - SPECIAL TOOL SP-3551
3 - BUSHING
4 - SPECIAL TOOL SP-5117
5 - BUSHING
6 - SPECIAL TOOL C-4171
7 - PUMP HOUSING
21 - 82 AUTOMATIC TRANSMISSION - 42REWJ
OIL PUMP (Continued)

(4) Lightly grip old bushing in vise or with pliers
and back remover tool out of bushing.
(5) Assemble Bushing Installer Tools C-4171 and
SP-5325 (Fig. 117).
(6) Slide new bushing onto Installer Tool SP-5325.
(7) Position reaction shaft support upright on a
clean smooth surface.
(8) Align bushing in bore. Then tap bushing into
place until Bushing Installer SP-5325 bottoms.
(9) Clean reaction shaft support thoroughly after
installing bushing.
CLEANING
Clean pump and support components with solvent
and dry them with compressed air.
INSPECTION
Check condition of the seal rings and thrust
washer on the reaction shaft support. The seal rings
do not need to be replaced unless cracked, broken, or
severely worn.
Inspect the pump and support components. Replace
the pump or support if the seal ring grooves or
machined surfaces are worn, scored, pitted, or dam-
aged. Replace the pump gears if pitted, worn
chipped, or damaged.
Inspect the pump bushing. Then check the reaction
shaft support bushing. Replace either bushing only if
heavily worn, scored or damaged. It is not necessary
to replace the bushings unless they are actually dam-
aged.
Clearance between outer gear and reaction shaft
housing should be 0.010 to 0.063 mm (0.0004 to
0.0025 in.). Clearance between inner gear and reac-
tion shaft housing should be 0.010 to 0.063 mm
(0.0004 to 0.0025 in.). Both clearances can be mea-
sured at the same time by installing the gears in the
pump body and measure pump component clearances
as follows:
(1) Position an appropriate piece of PlastigageŸ
across both gears.
(2) Align the plastigage to a flat area on the reac-
tion shaft housing.
(3) Install the reaction shaft to the pump housing.
(4) Separate the reaction shaft housing from the
pump housing and measure the PlastigageŸ follow-
ing the instructions supplied with it.
Clearance between inner gear tooth and outer gear
should be 0.08 to 0.19 mm (0.0035 to 0.0075 in.).
Measure clearance with an appropriate feeler gauge.
Clearance between outer gear and pump housing
should be 0.10 to 0.19 mm (0.004 to 0.0075 in.). Mea-
sure clearance with an appropriate feeler gauge.
ASSEMBLY
(1) Lubricate gear bore in pump housing with
transmission fluid.
(2) Lubricate pump gears with transmission fluid.
(3) Support pump housing on wood blocks (Fig.
118).
(4) Install outer gear in pump housing (Fig. 118).
Gear can be installed either way (it is not a one-way
fit).
(5) Install pump inner gear (Fig. 119).
Fig. 116 Staking Oil Pump Bushing
1 - NARROW BLADE
2 - BLUNT PUNCH
3 - TWO STAKES
Fig. 117 Replacing Reaction Shaft Support Bushing
1 - SPECIAL TOOL SP-1191
2 - SPECIAL TOOL SP-3633
3 - SPECIAL TOOL C-4171
4 - SPECIAL TOOL SP-5325
5 - REACTION SHAFT
6 - SPECIAL TOOL SP-5324
7 - BUSHING
WJAUTOMATIC TRANSMISSION - 42RE 21 - 83
OIL PUMP (Continued)

(12) Install new oil seal in pump with Special Tool
C-4193 and Tool Handle C-4171 (Fig. 122). Be sure
seal lip faces inward.
(13) Install new seal ring around pump housing.
Be sure seal is properly seated in groove.
(14) Lubricate lip of pump oil seal and O-ring seal
with transmission fluid.
OUTPUT SHAFT FRONT
BEARING
REMOVAL
(1) Remove overdrive unit from the vehicle.
(2) Remove overdrive geartrain from housing.
(3) Remove snap-ring holding output shaft front
bearing to overdrive geartrain. (Fig. 123).
(4) Pull bearing from output shaft.
INSTALLATION
(1) Place replacement bearing in position on
geartrain with locating retainer groove toward the
rear.
(2) Push bearing onto shaft until the snap-ring
groove is visible.
(3) Install snap-ring to hold bearing onto output
shaft.
(4) Install overdrive geartrain into housing.
(5) Install overdrive unit in vehicle.
OUTPUT SHAFT REAR
BEARING
REMOVAL
(1) Remove overdrive unit from the vehicle. (Refer
to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC/
OVERDRIVE - REMOVAL)
(2) Remove overdrive geartrain from housing.
(3) Remove snap-ring holding output shaft rear
bearing into overdrive housing (Fig. 124).
(4) Using a suitable driver inserted through the
rear end of housing, drive bearing from housing.
INSTALLATION
(1) Place replacement bearing in position in hous-
ing.
(2) Using a suitable driver, drive bearing into
housing until the snap-ring groove is visible.
(3) Install snap-ring to hold bearing into housing
(Fig. 124).
(4) Install overdrive geartrain into housing.
(5) Install overdrive unit in vehicle.
Fig. 122 Pump Oil Seal Installation
1 - PUMP BODY
2 - PUMP SEAL
3 - SPECIAL TOOL C-4193
Fig. 123 Output Shaft Front Bearing
1 - OUTPUT SHAFT FRONT BEARING
2 - SNAP-RING
3 - OUTPUT SHAFT
4 - GROOVE TO REAR
5 - OVERDRIVE GEARTRAIN
Fig. 124 Output Shaft Rear Bearing
1 - OUTPUT SHAFT REAR BEARING
2 - OVERDRIVE HOUSING
3 - SNAP-RING
WJAUTOMATIC TRANSMISSION - 42RE 21 - 85
OIL PUMP (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)

GEAR CASE AND PARK LOCK
(1) Remove locating ring from gear case.
(2) Remove park pawl shaft retaining bolt and
remove shaft, pawl and spring.
(3) Remove reaction plug snap-ring and remove
reaction plug.
(4) Remove output shaft seal.
CLEANING
Clean the geartrain and case components with sol-
vent. Dry all parts except the bearings with com-
pressed air. Allow bearings to air dry.
Do not use shop towels for wiping parts dry unless
the towels are made from a lint-free material. A suf-
ficient quantity of lint (from shop towels, cloths, rags,
etc.) could plug the transmission filter and fluid pas-
sages.
Discard the old case gasket and seals. Do not
attempt to salvage these parts. They are not reus-
able. Replace any of the overdrive unit snap-rings if
distorted or damaged.
Minor nicks or scratches on components can be
smoothed with crocus cloth. However, do not attempt
to reduce severe scoring on any components with
abrasive materials. Replace severely scored compo-
nents; do not try to salvage them.
INSPECTION
Check condition of the park lock components and
the overdrive case.
Check the bushings in the overdrive case. Replace
the bushings if severely scored or worn. Also replace
the case seal if loose, distorted, or damaged.
Examine the overdrive and direct clutch discs and
plates. Replace the discs if the facing is worn,
severely scored, or burned and flaking off. Replace
the clutch plates if worn, heavily scored, or cracked.
Check the lugs on the clutch plates for wear. The
plates should slide freely in the drum. Replace the
plates or drum if binding occurs.
Check condition of the annulus gear, direct clutch
hub, clutch drum and clutch spring. Replace the gear,
hub and drum if worn or damaged. Replace the
spring if collapsed, distorted, or cracked.
Be sure the splines and lugs on the gear, drum and
hub are in good condition. The clutch plates and
discs should slide freely in these components.
Inspect the thrust bearings and spring plate.
Replace the plate if worn or scored. Replace the bear-
ings if rough, noisy, brinnelled, or worn.
Inspect the planetary gear assembly and the sun
gear and bushings. If either the sun gear or the
bushings are damaged, replace the gear and bush-
ings as an assembly. The gear and bushings are not
serviced separately.The planetary carrier and pinions must be in good
condition. Also be sure the pinion pins are secure and
in good condition. Replace the carrier if worn or dam-
aged.
Inspect the overrunning clutch and race. The race
surface should be smooth and free of scores. Replace
the overrunning clutch assembly or the race if either
assembly is worn or damaged in any way.
Replace the shaft pilot bushing and inner bushing
if damaged. Replace either shaft bearing if rough or
noisy. Replace the bearing snap-rings if distorted or
cracked.
Check the machined surfaces on the output shaft.
These surfaces should clean and smooth. Very minor
nicks or scratches can be smoothed with crocus cloth.
Replace the shaft if worn, scored or damaged in any
way.
Inspect the output shaft bushings. The small bush-
ing is the intermediate shaft pilot bushing. The large
bushing is the overrunning clutch hub bushing.
Replace either bushing if scored, pitted, cracked, or
worn.
ASSEMBLY
GEARTRAIN AND DIRECT CLUTCH
(1) Soak direct clutch and overdrive clutch discs in
MopartATF +4, type 9602, transmission fluid. Allow
discs to soak for 10-20 minutes.
(2) Install new pilot bushing and clutch hub bush-
ing in output shaft if necessary (Fig. 155). Lubricate
bushings with petroleum jelly, or transmission fluid.
(3) Install annulus gear on output shaft, if
removed. Then install annulus gear retaining snap-
ring (Fig. 156).
Fig. 155 Output Shaft Pilot Bushing
1 - OUTPUT SHAFT HUB
2 - OVERRUNNING CLUTCH HUB BUSHING
3 - INTERMEDIATE SHAFT PILOT BUSHING
WJAUTOMATIC TRANSMISSION - 42RE 21 - 95
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)