2003 JEEP GRAND CHEROKEE stall

INSPECTION
Check sun gear and driving shell condition.
Replace the gear if damaged or if the bushings are
scored or worn. The bushings are not serviceable.
Replace the driving shell if worn, cracked or dam-
aged.Replace planetary gear sets if gears, pinion pins, or
carrier are damaged in any way. Replace the annulus
gears and supports if either component is worn or
damaged.
Inspect the geartrain spacers, thrust plates, snap-
rings, and thrust washers. Replace any of these parts
that are worn, distorted or damaged. Do not attempt
to reuse these parts.
The planetary gear thrust washers are different
sizes. The large diameter washers go on the front
planetary and the smaller washers go on the rear
planetary. All the washers have four locating tabs on
them. These tabs fit in the holes or slots provided in
each planetary gear.
Inspect the output shaft carefully. Pay particular
attention to the machined bushing/bearing surfaces
on the shaft and the governor valve shaft bore at the
shaft rear.
Replace the output shaft if the machined surfaces
are scored, pitted, or damaged in any way. Also
replace the shaft if the splines are damaged, or
exhibits cracks at any location (especially at the gov-
ernor valve shaft bore).
The annulus gears can be removed from their sup-
ports if necessary. Just remove the snap-rings and
separate the two parts when replacement is neces-
sary. In addition, the annulus gear bushings can be
replaced if severely worn, or scored. However it is not
necessary to replace the bushings if they only exhibit
normal wear. Check bushing fit on the output shaft
to be sure.
ASSEMBLY
(1) Lubricate output shaft and planetary compo-
nents with transmission fluid. Use petroleum jelly to
lubricate and hold thrust washers and plates in posi-
tion.
(2) Assemble rear annulus gear and support if dis-
assembled. Be sure support snap-ring is seated and
that shoulder-side of support faces rearward (Fig.
208).
(3) Install rear thrust washer on rear planetary
gear. Use enough petroleum jelly to hold washer in
place. Also be sure all four washer tabs are properly
engaged in gear slots.
(4) Install rear annulus over and onto rear plane-
tary gear (Fig. 208).
(5) Install assembled rear planetary and annulus
gear on output shaft (Fig. 209). Verify that assembly
is fully seated on shaft.
Fig. 206 Front Planetary And Annulus Gear
Disassembly
1 - FRONT ANNULUS
2 - THRUST WASHER
3 - THRUST PLATE
4 - FRONT THRUST WASHER
5 - FRONT PLANETARY
Fig. 207 Removing Driving Shell, Rear Planetary
And Rear Annulus
1 - REAR ANNULUS
2 - REAR PLANETARY
3 - DRIVING SHELL
4 - OUTPUT SHAFT
WJAUTOMATIC TRANSMISSION - 42RE 21 - 113
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(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)

INSPECTION
Replace the clutch discs if warped, worn, scored,
burned/charred, the lugs are damaged, or if the fac-
ing is flaking off. Replace the top and bottom pres-
sure plates if scored, warped, or cracked. Be sure the
driving lugs on the pressure and clutch plates are
also in good condition. The lugs must not be bent,
cracked or damaged in any way.
Replace the piston spring and wave spring if either
part is distorted, warped or broken.
Check the lug grooves in the clutch retainer. The
clutch and pressure plates should slide freely in the
slots. Replace the retainer if the grooves are worn or
damaged. Also check action of the check balls in the
retainer and piston. Each check ball must move
freely and not stick.
Replace the retainer bushing if worn, scored, or
doubt exists about bushing condition.
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.
Check condition of the fiber thrust washer and
metal output shaft thrust washer. Replace either
washer if worn or damaged.
Check condition of the seal rings on the input shaft
and clutch retainer hub. Replace the seal rings only
if worn, distorted, or damaged. The input shaft front
seal ring is teflon with chamfered ends. The rear ring
is metal with interlocking ends.
Check the input shaft for wear, or damage. Replace
the shaft if worn, scored or damaged in any way.
ASSEMBLY
(1) Soak clutch discs in transmission fluid while
assembling other clutch parts.
(2) Install new seal rings on clutch retainer hub
and input shaft, if necessary, (Fig. 227) and (Fig.
228).
(a) Be sure clutch hub seal ring is fully seated in
groove and is not twisted.
(3) Lubricate splined end of input shaft and clutch
retainer with transmission fluid. Then press input
shaft into retainer (Fig. 229). Use a suitably sized
press tool to support retainer as close to input shaft
as possible.
(4) Install input shaft snap-ring (Fig. 226).
(5) Invert retainer and press input shaft in oppo-
site direction until snap-ring is seated.
(6) Install new seals on clutch piston. Be sure lip
of each seal faces interior of clutch retainer.
(7) Lubricate lip of piston seals with generous
quantity of MopartDoor Ease. Then lubricate
retainer hub and bore with light coat of transmission
fluid.
(8) Install clutch piston in retainer. Use twisting
motion to seat piston in bottom of retainer. A thin
strip of plastic (about 0.0209thick), can be used to
guide seals into place if necessary.
CAUTION: Never push the clutch piston straight in.
This will fold the seals over causing leakage and
clutch slip. In addition, never use any type of metal
tool to help ease the piston seals into place. Metal
tools will cut, shave, or score the seals.
(9) Install piston spring in retainer and on top of
piston (Fig. 230). Concave side of spring faces down-
ward (toward piston).
(10) Install wave spring in retainer (Fig. 230). Be
sure spring is completely seated in retainer groove.
(11) Install bottom pressure plate (Fig. 225).
Ridged side of plate faces downward (toward piston)
and flat side toward clutch pack.
(12) Install first clutch disc in retainer on top of
bottom pressure plate. Then install a clutch plate fol-
lowed by a clutch disc until entire clutch pack is
installed (4 discs and 3 plates are required) (Fig.
225).
(13) Install top pressure plate.
(14) Install selective snap-ring. Be sure snap-ring
is fully seated in retainer groove.
(15) Using a suitable gauge bar and dial indicator,
measure clutch pack clearance (Fig. 231).
(a) Position gauge bar across the clutch drum
with the dial indicator pointer on the pressure
plate (Fig. 231).
(b) Using two small screw drivers, lift the pres-
sure plate and release it.
Fig. 226 Removing Input Shaft Snap-Ring
1 - REAR CLUTCH RETAINER
2 - INPUT SHAFT SNAP-RING
3 - SNAP-RING PLIERS
21 - 120 AUTOMATIC TRANSMISSION - 42REWJ
REAR CLUTCH (Continued)

(c) Zero the dial indicator.
(d) Lift the pressure plate until it contacts the
snap-ring and record the dial indicator reading.Clearance should be 0.559 - 0.914 mm (0.022 -
0.036 in.). If clearance is incorrect, steel plates, discs,
selective snap ring and pressure plates may have to
be changed.
Fig. 227 Rear Clutch Retainer And Input Shaft Seal
Ring Installation
1 - REAR CLUTCH RETAINER HUB SEAL RING
2 - INPUT SHAFT SEAL RINGS
Fig. 228 Input Shaft Seal Ring Identification
1 - PLASTIC REAR SEAL RING
2 - TEFLON FRONT SEAL RING (SQUEEZE RING TOGETHER
SLIGHTLY BEFORE INSTALLATION FOR BETTER FIT)
Fig. 229 Pressing Input Shaft Into Rear Clutch
Retainer
1 - INPUT SHAFT
2 - REAR CLUTCH RETAINER
3 - PRESS RAM
Fig. 230 Piston Spring/Wave Spring Position
1 - REAR CLUTCH RETAINER
2 - PISTON SPRING
3 - WAVE SPRING
4 - CLUTCH PISTON
WJAUTOMATIC TRANSMISSION - 42RE 21 - 121
REAR CLUTCH (Continued)

The selective snap-ring thicknesses are:
²0.107-0.109 in.
²0.098-0.100 in.
²0.095-0.097 in.
²0.083-0.085 in.
²0.076-0.078 in.
²0.071-0.073 in.
²0.060-0.062 in.
(16) Coat rear clutch thrust washer with petro-
leum jelly and install washer over input shaft and
into clutch retainer (Fig. 232). Use enough petroleum
jelly to hold washer in place.REAR SERVO
DESCRIPTION
The rear (low/reverse) servo consists of a single
stage or diameter piston and a spring loaded plug.
The spring is used to cushion the application of the
rear (low/reverse) band.
OPERATION
While in the de-energized state (no pressure
applied), the piston is held up in its bore by the pis-
ton spring. The plug is held down in its bore, in the
piston, by the plug spring. When pressure is applied
to the top of the piston, the plug is forced down in its
bore, taking up any clearance. As the piston moves, it
causes the plug spring to compress, and the piston
moves down over the plug. The piston continues to
move down until it hits the shoulder of the plug and
fully applies the band. The period of time from the
initial application, until the piston is against the
shoulder of the plug, represents a reduced shocking
of the band that cushions the shift.
DISASSEMBLY
(1) Remove small snap-ring and remove plug and
spring from servo piston (Fig. 233).
(2) Remove and discard servo piston seal ring.
CLEANING
Remove and discard the servo piston seal ring (Fig.
234). Then clean the servo components with solvent
and dry with compressed air. Replace either spring if
collapsed, distorted or broken. Replace the plug and
piston if cracked, bent, or worn. Discard the servo
snap-rings and use new ones at assembly.
Fig. 231 Checking Rear Clutch Pack Clearance
1 - DIAL INDICATOR
2 - PRESSURE PLATE
3 - SNAP-RING
4-STAND
5 - REAR CLUTCH
6 - GAUGE BAR
Fig. 232 Installing Rear Clutch Thrust Washer
1 - REAR CLUTCH RETAINER
2 - REAR CLUTCH THRUST WASHER
Fig. 233 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
21 - 122 AUTOMATIC TRANSMISSION - 42REWJ
REAR CLUTCH (Continued)