2002 JEEP GRAND CHEROKEE front differential

PINION GEAR/RING GEAR
REMOVAL
NOTE: The ring gear and pinion are serviced as a
matched set. Nevar replace one gear without replac-
ing the other matching gear.
(1) Raise and support vehicle
(2) Mark pinion companion flange and propeller
shaft for installation alignment.
(3) Remove propeller shaft from pinion companion
flange and tie propeller shaft to underbody.
(4) Remove differential from axle housing.
(5) Place differential case in a vise with soft metal
jaw (Fig. 51).
(6) Remove bolts holding ring gear to differential
case.
NOTE: On Veri-LokTdifferential the side bearing
and oil feed plenum must be removed before
removing the ring gear bolts.
(7) Driver ring gear off the differential case with a
rawhide hammer (Fig. 51).(8) With Spanner Wrench 6958 and a short length
of 1 in. pipe, hold pinion companion flange and
remove pinion nut and washer (Fig. 52).
(9) Remove pinion companion flange from pinion
shaft with Remover C-452 and Flange Wrench
C-3281.
Fig. 50 DIFFERENTIAL CASE BEARING
1 - INSTALLER
2 - HANDLE
Fig. 51 RING GEAR
1 - DIFFERENTIAL CASE
2 - RING GEAR
3 - HAMMER
Fig. 52 Pinion Flange
1 - PINION FLANGE
2 - FRONT AXLE
3 - SPANNER WRENCH
WJFRONT AXLE - 186FBI 3 - 45
DIFFERENTIAL CASE BEARINGS (Continued)

(5) Apply a light coating of gear lubricant on the
lip of pinion seal and install seal with an appropriate
installer (Fig. 60).
(6) Install rear pinion bearing and oil slinger/depth
shim onto the pinion shaft with Installer 6448 and a
press (Fig. 61).
(7) Install anewcollapsible spacer on pinion shaft
and install the pinion into the housing (Fig. 62).
(8) Install pinion companion flange, with Installer
W-162-B, Cup 8109 and Spanner Wrench 6958.(9) Install pinion washer and anewnut onto the
pinion gear and tighten the nut to 298 N´m (220 ft.
lbs.).Do not over-tighten.
CAUTION: Never loosen pinion gear nut to decrease
pinion rotating torque and never exceed specified
preload torque. If preload torque is exceeded a new
collapsible spacer must be installed.
(10) Use Flange Wrench 6958, a length of 1 in.
pipe and a torque wrench set at 500 N´m (368 ft. lbs.)
and crush collapsible spacer until bearing end play is
taken up (Fig. 63).
(11) Slowly tighten the nut in 6.8 N´m (5 ft. lb.)
increments until the required rotating torque is
achieved. Measure the rotating torque frequently to
avoid over crushing the collapsible spacer (Fig. 64).
(12) Rotate the pinion a minimum of ten times.
Verify pinion rotates smoothly and check rotating
torque with an inch pound torque wrench (Fig. 64).
Pinion gear rotating torque is:
²Original Bearings: 1 to 2.25 N´m (10 to 20 in.
lbs.).
²New Bearings: 1.7 to 3.4 N´m (15 to 30 in. lbs.).
(13) Invert the differential case and start two ring
gear bolts. This will provide case-to-ring gear bolt
hole alignment.
Fig. 60 PINION SEAL
1 - HANDLE
2 - INSTALLER
Fig. 61 REAR PINION BEARING
1 - INSTALLER
2 - OIL SLINGER
3 - PINION GEAR
4 - REAR PINION BEARING
5 - PRESS
Fig. 62 COLLAPSIBLE PRELOAD SPACER
1 - COLLAPSIBLE SPACER
2 - SHOULDER
3 - PINION GEAR
4 - DEPTH SHIM
5 - REAR BEARING
3 - 48 FRONT AXLE - 186FBIWJ
PINION GEAR/RING GEAR (Continued)

(14) Invert the differential case in the vise.
(15) Install new ring gear bolts and alternately
tighten to 108 N´m (80 ft. lbs.) (Fig. 65).
CAUTION: Never reuse the ring gear bolts. The
bolts can fracture causing extensive damage.
NOTE: If equipped with Veri-LokTdifferential install
oil feed plenum and side bearing.
(16) Install differential in housing and verify dif-
ferential bearing preload, gear mesh and contact pat-
tern. Refer to Adjustment for procedure.
(17) Install differential cover and fill with gear
lubricant.
(18) Install propeller shaft with reference marks
aligned.
(19) Remove supports and lower vehicle.
Fig. 63 Pinion Nut
1 - PINION FLANGE
2 - FRONT AXLE
3 - SPANNER WRENCH
Fig. 64 PINION ROTATING TORQUE
1 - TORQUE WRENCH
2 - PINION YOKE/FLANGE
Fig. 65 RING GEAR BOLTS
1 - TORQUE WRENCH
2 - RING GEAR BOLTS
3 - RING GEAR
4 - DIFFERENTIAL CASE
WJFRONT AXLE - 186FBI 3 - 49
PINION GEAR/RING GEAR (Continued)

peak-noise range. If the noise stops or changes
greatly:
²Check for insufficient lubricant.
²Incorrect ring gear backlash.
²Gear damage.
Differential side gears and pinions can be checked
by turning the vehicle. They usually do not cause
noise during straight-ahead driving when the gears
are unloaded. The side gears are loaded during vehi-
cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side±gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by a:
²Damaged drive shaft.
²Missing drive shaft balance weight(s).
²Worn or out-of-balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front-end components
or engine/transmission mounts. These components
can contribute to what appears to be a rearend vibra-
tion. Do not overlook engine accessories, brackets
and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
3 - 52 REAR AXLE - 198RBIWJ
REAR AXLE - 198RBI (Continued)

PINION DEPTH MEASUREMENT
Measurements are taken with pinion bearing cups
and pinion bearings installed in the housing. Take
measurements with Pinion Gauge Set and Dial Indi-
cator C-3339 (Fig. 8).
(1) Assemble Pinion Height Block 6739, Pinion
Block 6735 and rear pinion bearing onto Screw 6741
(Fig. 8).
(2) Insert assembled height gauge components,
rear bearing and screw into the housing through pin-
ion bearing cups (Fig. 9).
(3) Install front pinion bearing and Cone-nut 6740
hand tight (Fig. 8).
(4) Place Arbor Disc 6732 on Arbor D-115-3 in posi-
tion in the housing side bearing cradles (Fig. 10).
Install differential bearing caps on Arbor Discs and
tighten cap bolts to 41 N´m (30 ft. lbs.).
NOTE: Arbor Discs 6732 has different step diame-
ters to fit other axles. Choose proper step for axle
being serviced.
(5) Assemble Dial Indicator C-3339 into Scooter
Block D-115-2 and secure set screw.(6) Place Scooter Block/Dial Indicator in position
in the housing so dial probe and scooter block are
flush against the rearward surface of the pinion
height block (Fig. 8). Hold scooter block in place and
zero the dial indicator face to the pointer. Tighten
dial indicator face lock screw.
(7) With scooter block still in position against the
pinion height block, slowly slide the dial indicator
probe over the edge of the pinion height block.
Fig. 8 PINION GEAR DEPTH GAUGE TOOLS
1 - DIAL INDICATOR
2 - ARBOR
3 - PINION HEIGHT BLOCK
4 - CONE
5 - SCREW
6 - PINION BLOCK
7 - SCOOTER BLOCK
8 - ARBOR DISC
Fig. 9 PINION HEIGHT BLOCK
1 - PINION BLOCK
2 - PINION HEIGHT BLOCK
Fig. 10 GAUGE TOOLS IN HOUSING
1 - ARBOR DISC
2 - PINION BLOCK
3 - ARBOR
4 - PINION HEIGHT BLOCK
3 - 58 REAR AXLE - 198RBIWJ
REAR AXLE - 198RBI (Continued)

(6) If the rotating torque is low, use Spanner
Wrench 6958 to hold the pinion yoke (Fig. 37), and
tighten the pinion nut in 6.8 N´m (5 ft. lbs.) incre-
ments until the proper rotating torque is achieved.
CAUTION: If maximum tightening torque is reached
prior to reaching required rotating torque, the col-
lapsible spacer may have been damaged. Replace
the collapsible spacer.
(7) Install the propeller shaft with reference marks
aligned.
(8) Add gear lubricant to the differential if neces-
sary.
(9) Install brake rotors and calipers.
(10) Install wheel and tire assemblies.
(11) Lower the vehicle.
COLLAPSIBLE SPACER
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies.
(3) Remove rear brake calipers and rotors.
(4) Mark propeller shaft and pinion yoke for
installation reference and remove propeller shaft.
(5) Rotate pinion gear a minimum of ten times and
verify pinion rotates smoothly.
(6) Record rotate torque of the pinion gear, with an
inch pound torque wrench.
(7) Hold pinion yoke with Spanner Wrench 6958
and remove pinion nut and washer (Fig. 38).
(8) Remove pinion yoke with Remover C-452 and
Wrench C-3281 (Fig. 39).(9) Remove pinion shaft seal with Remover 7794-A
and slide hammer (Fig. 40).
(10) Remove front pinion bearing using a pair of
pick tools to pull the bearing off the pinion gear
shaft.
NOTE: If the pinion bearing becomes bound on the
pinion shaft, lightly tap the end of the shaft with a
rawhide/rubber mallet.
(11) Remove the collapsible spacer.
INSTALLATION
(1) Install anewcollapsible spacer on pinion
shaft.
(2) Install pinion front bearing on the pinion shaft.
Fig. 37 PINION SHAFT NUT
1 - SPANNER WRENCH
2 - PIPE
3 - TORQUE WRENCH
Fig. 38 PINION YOKE HOLDER
1 - 1 in. PIPE
2 - PINION YOKE
3 - SPANNER WRENCH
4 - LOWER CONTROL ARM
Fig. 39 PINION YOKE PULLER
1 - WRENCH
2 - PINION YOKE
3 - PULLER
WJREAR AXLE - 198RBI 3 - 73
PINION SEAL (Continued)

(12) Install cover and tighten bolts in a criss-cross
pattern to 41 N´m (30 ft. lbs.).
(13) Refill the differential with Mopar Hypoid
Gear Lubricant or equivalent to bottom of the fill
plug hole.
(14) Install fill hole plug.
(15) Remove support and lower the vehicle.
DIFFERENTIAL-TRAC-LOC
DIAGNOSIS AND TESTING
The most common problem is a chatter noise when
turning corners. Before removing the unit for repair,
drain, flush and refill the axle with the specified
lubricant. A container of Mopar Trac-loktLubricant
(friction modifier) should be added after repair ser-
vice or during a lubricant change.
After changing the lubricant, drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu-
ver will pump lubricant through the clutches. This
will correct the condition in most instances. If the
chatter persists, clutch damage could have occurred.
DIFFERENTIAL TEST
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.
(4) Remove wheel and bolt Special Tool 6790 or
equivalent tool to studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 56).
(6) If rotating torque is less than 41 N´m (56 ft.
lbs.) or more than 271 N´m (200 ft. lbs.) on either
wheel the unit should be serviced.
DISASSEMBLY
(1) Clamp side gear Holding Fixture 6965 in a vise
and position the differential case on the Holding Fix-
ture (Fig. 57).
Fig. 56 ROTATING TORQUE TEST
1 - SPECIAL TOOL WITH BOLT IN CENTER HOLE
2 - TORQUE WRENCH
Fig. 57 DIFFERENTIAL CASE FIXTURE
1 - HOLDING FIXTURE
2 - VISE
3 - DIFFERENTIAL
WJREAR AXLE - 198RBI 3 - 79
DIFFERENTIAL (Continued)

REAR AXLE - 226RBA
TABLE OF CONTENTS
page page
REAR AXLE - 226RBA
DESCRIPTION.........................90
OPERATION...........................90
DIAGNOSIS AND TESTING................92
REMOVAL.............................95
INSTALLATION.........................96
ADJUSTMENTS........................97
SPECIFICATIONS......................105
SPECIAL TOOLS.......................106
AXLE SHAFTS
REMOVAL............................109
INSTALLATION........................109
AXLE BEARINGS/SEALS
REMOVAL............................109
INSTALLATION........................110
PINION SEAL
REMOVAL............................111
INSTALLATION........................112
COLLAPSIBLE SPACER
REMOVAL............................113INSTALLATION........................114
DIFFERENTIAL
REMOVAL............................115
DISASSEMBLY........................117
ASSEMBLY...........................117
INSTALLATION........................117
DIFFERENTIAL - TRAC-LOK
DIAGNOSIS AND TESTING...............119
DISASSEMBLY........................119
CLEANING...........................121
INSPECTION.........................121
ASSEMBLY...........................121
DIFFERENTIAL CASE BEARINGS
REMOVAL............................123
INSTALLATION........................123
PINION GEAR/RING GEAR
REMOVAL............................124
INSTALLATION........................126
REAR AXLE - 226RBA
DESCRIPTION
The Rear Beam-design Aluminum (RBA) axle hous-
ing has an aluminum center casting (differential
housing) with axle shaft tubes extending from either
side. The tubes are pressed into the differential hous-
ing to form a one-piece axle housing. The axle has
semi-floating axle shafts, meaning that vehicle load
is supported by the axle shaft and bearings.
The differential case is a one-piece design. Differen-
tial bearing preload and ring gear backlash is adjusted
with selective shims. Pinion bearing preload is set and
maintained by the use of a collapsible spacer. The cover
provides a means for inspection and service.
Optional Trac-Loktdifferential differential has a
one-piece differential case, and the same internal
components as a standard differential, plus two
clutch disc packs.
Optional Vari-Loktdifferential has a one-piece dif-
ferential case which contains the gerotor pump
assembly and the clutch mechinism. The unit is ser-
viced only as an assembly.
OPERATION
The axle receives power from the transfer case
through the front propeller shaft. The front propellershaft is connected to the pinion gear which rotates
the differential through the gear mesh with the ring
gear bolted to the differential case. The engine power
is transmitted to the axle shafts through the pinion
mate and side gears. The side gears are splined to
the axle shafts.
STANDARD DIFFERENTIAL
During straight-ahead driving the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 1).
When turning corners, the outside wheel must travel
a greater distance than the inside wheel to complete a
turn. The difference must be compensated for to prevent
the tires from scuffing and skidding through turns. To
accomplish this, the differential allows the axle shafts
to turn at unequal speeds (Fig. 2). In this instance, the
input torque applied to the pinion gears is not divided
equally. The pinion gears now rotate around the pinion
mate shaft in opposite directions. This allows the side
gear and axle shaft attached to the outside wheel to
rotate at a faster speed.
3 - 90 REAR AXLE - 226RBAWJ