2002 JEEP GRAND CHEROKEE preload

(9) Install a Pilot Stud C-3288-B at the left side of
the differential housing. Attach Dial Indicator C-3339
to stud. Load the lever adapter against the opposite
side of the housing (Fig. 40) and zero the indicator.
(10) Spread housing enough to remove the differ-
ential case from the housing. Measure the distance
with the dial indicator (Fig. 41).
CAUTION: Never spread the housing over 0.50 mm
(0.020 in). If housing is over-spread, it could dis-
torted and damaged the housing.
(11) Remove the dial indicator.
(12) Hold differential case in position and remove
differential bearing cap bolts and caps.
(13) Remove differential from the housing and tag
differential bearing cups to ensure location (Fig. 42).
(14) Remove differential case preload shims from
the axle housing.
(15) Remove spreader from housing. Tag differen-
tial bearing preload shims to ensure correct location.
Fig. 40 DIAL INDICATOR LOCATION
1 - CLAMP
2 - DIAL INDICATOR
3 - LEVER ADAPTER
4 - SPREADER
5 - PILOT STUDFig. 41 SPREAD DIFFERENTIAL HOUSING
1 - DIAL INDICATOR
2 - SPREADER
Fig. 42 DIFFERENTIAL CASE REMOVAL
1 - DIFFERENTIAL HOUSING
2 - DIFFERENTIAL CASE
3 - BEARING CUPS
WJFRONT AXLE - 186FBI 3 - 41
DIFFERENTIAL (Continued)

INSTALLATION
NOTE: If replacement differential bearings or differ-
ential case are being installed, differential side
bearing shim requirements may change. Refer to
Adjustments (Differential Bearing Preload and Gear
Backlash) to determine the proper shim selection.
(1) Position Spreader W-129-B with Adapter Kit
6987B on differential locating holes. Install hold
down clamps and tighten the tool turnbuckle finger-
tight.
(2) Install a Pilot Stud C-3288-B at the left side of
the differential housing. Attach Dial Indicator C-3339
to pilot stud. Load the indicator plunger against the
opposite side of the housing and zero the indicator.
(3) Spread the housing enough to install the case
in the housing. Measure the distance with the dial
indicator.
CAUTION: Never spread the housing over 0.50 mm
(0.020 in). If housing is over-spread, it could dis-
torted and damaged the housing.
(4) Remove the dial indicator.
(5) Install differential case in the housing (Fig.
46). Make sure the differential bearing cups remain
on the bearings and the preload shims remain
between the face of the bearing cup and housing. Tap
the differential case to ensure the bearings cups and
shims are fully seated in the housing.
CAUTION: On a Vari-lokTdifferential the oil feed
tube must be pointed at the bottom of the housing.
If differential is installed with the oil feed tube
pointed at the top, the anti-rotation tabs will be
damaged.
(6) Install the bearing caps at their original loca-
tions (Fig. 47).
(7) Loosely install differential bearing cap bolts.
(8) Remove axle housing spreader.
(9) Tighten the bearing cap bolts to 61 N´m (45 ft.
lbs.).
(10) Install the hub bearings and axle shafts.
Fig. 46 DIFFERENTIAL CASE REMOVAL
1 - DIFFERENTIAL HOUSING
2 - DIFFERENTIAL CASE
3 - BEARING CUPS
Fig. 47 Bearing Cap Reference
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
WJFRONT AXLE - 186FBI 3 - 43
DIFFERENTIAL (Continued)

(11) Apply a bead 6.35mm (1/4 inch) of red Mopar
Silicone Rubber Sealant or equivalent to the housing
cover (Fig. 48).
CAUTION: If cover is not installed within 3 to 5 min-
utes, the cover must be cleaned and new RTV
applied or adhesion quality will be compromised.
(12) Install differential cover and tighten cover
bolts in a criss-cross pattern to 41 N´m (30 ft. lbs.).
(13) Fill differential with gear lubricant to bottom
of the fill plug hole.
(14) Tighten fill plug to 34 N´m (25 ft. lbs.).
(15) Remove support and lower the vehicle.
DIFFERENTIAL CASE
BEARINGS
REMOVAL
(1) Remove differential case from housing.
(2) Remove bearings from the differential case
with Puller C-293-PA, Adapters 8352 and Plug
SP-3289 (Fig. 49).
INSTALLATION
NOTE: If replacement differential side bearings or
differential case are being installed, differential side
bearing shim requirements may change. Refer to
Adjustments (Differential Bearing Preload and Gear
Backlash) to determine the proper shim selection.
CAUTION: Vari-lokTplenum must be fully seated
against the differential case prior to installing the
ring gear side differential bearing.
(1) Install differential side bearings with Handle
C-4171 and Installer C-3726-A (Fig. 50).
(2) Install differential in housing.
Fig. 48 DIFFERENTIAL COVER
1 - COVER
2 - SEALANT
3 - SEALANT BEADFig. 49 DIFFERENTIAL CASE BEARING
1 - ADAPTERS
2 - BEARING
3 - DIFFERENTIAL
4 - PLUG
5 - PULLER
3 - 44 FRONT AXLE - 186FBIWJ
DIFFERENTIAL (Continued)

(10) Remove pinion gear and collapsible spacer
from housing (Fig. 53).
(11) Remove front pinion bearing cup, bearing, oil
slinger and pinion seal with Remover D-158 and
Handle C-4171 (Fig. 54).(12) Remove rear pinion bearing cup (Fig. 55) with
Remover C-4307 and Handle C-4171.
(13) Remove collapsible preload spacer from pinion
gear (Fig. 56).
(14) Remove rear pinion bearing from the pinion
with Puller/Press C-293-PA and Adapters C-293-42
(Fig. 57). Remove oil slinger/pinion depth shim from
the pinion shaft and record thickness.
INSTALLATION
NOTE: Pinion depth shims are placed between the
rear pinion bearing cone and the pinion head to
achieve proper ring and pinion gear mesh. If ring
and pinion gears are reused, the pinion oil slinger/
depth shim should not require replacement. Refer
to Adujstments (Pinion Gear Depth) to select the
proper thickness shim before installing pinion gear.
(1) Apply Mopar Door Ease or equivalent lubricant
to outside surface of pinion bearing cups.
(2) Install rear bearing cup with Installer C-4308
and Handle C-4171 and verify cup is seated (Fig. 58).
(3) Install bearing cup with Installer D-144 and
Handle C-4171 (Fig. 59) and verify cup is seated.
(4) Install front pinion bearing, and oil slinger if
equipped.
Fig. 53 REMOVE PINION GEAR
1 - RAWHIDE HAMMER
Fig. 54 FRONT PINION BEARING CUP
1 - REMOVER
2 - HANDLE
Fig. 55 REAR PINION BEARING CUP
1 - REMOVER
2 - HANDLE
3 - 46 FRONT AXLE - 186FBIWJ
PINION GEAR/RING GEAR (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)

REAR AXLE - 198RBI
TABLE OF CONTENTS
page page
REAR AXLE - 198RBI
DESCRIPTION.........................50
OPERATION...........................50
DIAGNOSIS AND TESTING................51
REMOVAL.............................55
INSTALLATION.........................56
ADJUSTMENTS........................56
SPECIFICATIONS.......................65
SPECIAL TOOLS.......................66
AXLE SHAFTS
REMOVAL.............................69
INSTALLATION.........................69
AXLE BEARINGS/SEALS
REMOVAL.............................69
INSTALLATION.........................70
PINION SEAL
REMOVAL.............................71
INSTALLATION.........................71
COLLAPSIBLE SPACER
REMOVAL.............................73INSTALLATION.........................73
DIFFERENTIAL
REMOVAL.............................75
DISASSEMBLY.........................77
ASSEMBLY............................77
INSTALLATION.........................77
DIFFERENTIAL-TRAC-LOC
DIAGNOSIS AND TESTING................79
DISASSEMBLY.........................79
CLEANING............................82
INSPECTION..........................82
ASSEMBLY............................82
DIFFERENTIAL CASE BEARINGS
REMOVAL.............................83
INSTALLATION.........................84
PINION GEAR/RING GEAR
REMOVAL.............................84
INSTALLATION.........................86
REAR AXLE - 198RBI
DESCRIPTION
The Rear Beam-design Iron (RBI) axle housing has
an iron center casting with axle shaft tubes extend-
ing from either side. The tubes are pressed into and
welded to the differential housing to form a one-piece
axle housing. The axles has semi-floating axle shafts,
meaning that loads are supported by the axle shaft
and bearings. The axle shafts are retained by bearing
retainer plates on the axles which are bolted to
flanges at the outboard end of the axle tubes.
The differential case is a one-piece design. Differ-
ential bearing preload and ring gear backlash is
adjusted by the use of selective spacer shims. Pinion
bearing preload is set and maintained by the use of a
collapsible spacer. A differential cover provides a
means for inspection and service.
Axles with optional Trac-Loktdifferential have a
one-piece differential case, and the same internal
components as a standard differential, plus two
clutch disc packs.
OPERATION
The axle receives power from the transmission/
transfer case through the rear propeller shaft. Therear propeller shaft 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 - 50 REAR AXLE - 198RBIWJ

TRAC-LOKTDIFFERENTIAL
This differentials clutches are engaged by two con-
current forces. The first being the preload force
exerted through Belleville spring washers within the
clutch packs. The second is the separating forces gen-
erated by the side gears as torque is applied through
the ring gear (Fig. 3).
This design provides the differential action needed
for turning corners and for driving straight ahead
during periods of unequal traction. When one wheel
looses traction, the clutch packs transfer additional
torque to the wheel having the most traction. This
differential resist wheel spin on bumpy roads and
provide more pulling power when one wheel looses
traction. Pulling power is provided continuously until
both wheels loose traction. If both wheels slip due to
unequal traction, Trac-lokŸ operation is normal. Inextreme cases of differences of traction, the wheel
with the least traction may spin.DIAGNOSIS AND TESTING
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, tooth contact, worn/damaged
gears, or the carrier housing not having the proper
offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
Fig. 1 STRAIGHT AHEAD DRIVING
1 - WHEELS ROTATE AT CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 2 DIFFERENTIAL ON TURNS
1 - PINION GEARS ROTATE ON PINION SHAFT
Fig. 3 TRAC-LOK LIMITED SLIP DIFFERENTIAL
1 - CASE
2 - RING GEAR
3 - DRIVE PINION
4 - PINION GEAR
5 - MATE SHAFT
6 - CLUTCH PACK
7 - SIDE GEAR
8 - CLUTCH PACK
WJREAR AXLE - 198RBI 3 - 51
REAR AXLE - 198RBI (Continued)