2003 JEEP GRAND CHEROKEE spec

GEAR CONTACT PATTERN
The ring gear and pinion teeth contact patterns
will show if the pinion depth is correct in the hous-
ing. It will also show if the ring gear backlash has
been adjusted correctly. The backlash can be adjusted
within specifications to achieve desired tooth contact
patterns.
(1) Apply a thin coat of hydrated ferric oxide or
equivalent to the drive and coast side of the ring gear
teeth.
(2) Wrap, twist and hold a shop towel around the
pinion yoke to increase the turning resistance of the
pinion. This will provide a more distinct contact pat-
tern.
(3) With a boxed end wrench on a ring gear bolt,
rotate the differential case one complete revolution in
both directions while a load is being applied from
shop towel.
The areas on the ring gear teeth with the greatest
degree of contact against the pinion teeth will squee-
gee the compound to the areas with the least amount
of contact. Note and compare patterns on the ring
gear teeth to Gear Tooth Contact Patterns chart (Fig.
24) and adjust pinion depth and gear backlash as
necessary.
Fig. 23 BACKLASH SHIM
WJREAR AXLE - 198RBI 3 - 63
REAR AXLE - 198RBI (Continued)

DIFFERENTIAL BEARING PRELOAD CHECK
The final check on the differential assembly before
installing the axles is torque to rotate pinion and dif-
ferential combined. This will verify the correct differ-
ential bearing preload.Torque to rotate the differential and pinion should
be the torque to rotate the pinion plus 0.79-1.24 N´m
(7-11 in. lbs.).
SPECIFICATIONS
AXLE SPECIFICATIONS
DESCRIPTION SPECIFICATION
Axle Ratio 3.07, 3.31, 3.55, 3.73, 4.11
Differential Bearing Preload 0.1 mm (0.004 in.)
Ring Gear Diameter 198 mm (7.795 in.)
Ring Gear Backlash 0.12-0.20 mm (0.005-0.008 in.)
Pinion Gear Std. Depth 96.85 mm (3.813 in.)
Pinion Bearing Preload - Original Bearings 1-2 N´m (10-20 in. lbs.)
Pinion Bearing Preload - New Bearings 1.7-3.9 N´m (15-35 in. lbs.)
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Differential Cover Bolts 41 30 -
Bearing Cap Bolts 77 57 -
Ring Gear Bolts 129-142 95-105 -
Pinion Nut Minimum 272 200 -
Pinion Mate Shaft Screw 16.25 12 -
Axle Bearing Retainer Plate
Nuts61 45 -
WJREAR AXLE - 198RBI 3 - 65
REAR AXLE - 198RBI (Continued)

SPECIAL TOOLS
PULLER C-293-PA
ADAPTER 8352
ADAPTER C-293-40
PLUG SP-3289
Puller C-452
Wrench C-3281
Spanner Wrench 6958
INSTALLER 8112
CUP 8109
3 - 66 REAR AXLE - 198RBIWJ
REAR AXLE - 198RBI (Continued)

(4) Tighten the nut to 271 N´m (200 ft. lbs.).
CAUTION: Never loosen pinion gear nut to decrease
pinion rotating torque and never exceed specified
preload torque. If preload torque or rotating torque
is exceeded a new collapsible spacer must be
installed.
(5) Rotate the pinion gear a minimum of ten times
and verify pinion rotates smoothly. Rotate pinion
shaft an inch pound torque wrench. Rotating torque
should be equal to recorded reading plus an addi-
tional 0.56 N´m (5 in. lbs.) (Fig. 36).
Fig. 33 PINION SEAL
1 - REMOVER
2 - SLIDE HAMMER
3 - PINION SEAL
Fig. 34 PINION SEAL
1 - HANDLE
2 - INSTALLER
Fig. 35 PINION YOKE
1 - PINION YOKE
2 - DIFFERENTIAL HOUSING
Fig. 36 PINION ROTATING TORQUE
1 - TORQUE WRENCH
2 - PINION YOKE
3 - 72 REAR AXLE - 198RBIWJ
PINION SEAL (Continued)

(3) Apply a light coating of gear lubricant on the
lip of pinion seal and install seal with an appropriate
installer (Fig. 41).
(4) Install yoke with Screw 8112, Cup 8109 and
Spanner Wrench 6958 (Fig. 42).
(5) Install yoke washer andnewnut on the pinion
gear. Tighten the nut to 271 N´m (200 ft. lbs.).
CAUTION: Never loosen pinion gear nut to decrease
pinion rotating torque and never exceed specified
preload torque. If preload torque or rotating torque
is exceeded a new collapsible spacer must be
installed.
(6) Using yoke with Spanner Wrench 6958 and a
torque wrench set at 474 N´m (350 ft. lbs.), (Fig. 43)
slowly tighten the nut in 6.8 N´m (5 ft. lbs.) incre-
ments until the rotating torque is achieved. Measurethe rotating torque frequently to avoid over crushing
the collapsible spacer (Fig. 44).
NOTE: If more than 474 N´m (350 ft. lbs.) torque is
required to crush the collapsible spacer, the spacer
is defective and must be replaced.
Fig. 40 PINION SEAL REMOVER
1 - REMOVER
2 - SLIDE HAMMER
3 - PINION SEAL
Fig. 41 PINION SEAL INSTALLER
1 - HANDLE
2 - INSTALLER
Fig. 42 PINION YOKE INSTALLER
1 - INSTALLER
2 - PINION YOKE
3 - SPANNER WRENCH
Fig. 43 PINION NUT
1 - SPANNER WRENCH
2 - PIPE
3 - TORQUE WRENCH
3 - 74 REAR AXLE - 198RBIWJ
COLLAPSIBLE SPACER (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)

(15) Remove top side gear, clutch pack retainer
and clutch pack. Keep plates in correct order during
removal (Fig. 65).
(16)
Remove differential case from the Holding Fix-
ture. Remove side gear, clutch pack retainer and clutch
pack. Keep plates in correct order during removal.
CLEANING
Clean all components in cleaning solvent and dry
components with compressed air.
INSPECTION
Inspect clutch pack plates for wear, scoring or dam-
age. Replace both clutch packs if any one component
in either pack is damaged. Inspect side and pinion
gears for cracks chips or damage and replace as nec-
essary. Inspect differential case and pinion shaft and
replace if worn or damaged.
ASSEMBLY
NOTE: New Plates and discs with fiber coating (no
grooves or lines) must be presoaked in Friction
Modifier before assembly. Soak plates and discs for
a minimum of 20 minutes.
(1) Lubricate components with gear lubricant.
(2) Assemble clutch discs into packs and secure
disc packs with retaining clips (Fig. 66).NOTE: Dished plate is position with the convex side
against the side gear.
(3) Position assembled clutch disc packs on the
side gear hubs.
(4) Install clutch pack and side gear in the ring
gear side of the differential case (Fig. 67).Verify
clutch pack retaining clips are in position and
seated in the case pockets.
Fig. 65 SIDE GEARS AND CLUTCH DISCS
1 - DIFFERENTIAL CASE
2 - RETAINER
3 - SIDE GEAR AND CLUTCH DISC PACK
Fig. 66 CLUTCH PACK
1 - DISCS
2 - DISHED PLATE
3 - RETAINER
4 - SIDE GEAR
5 - RETAINER
6 - PLATES
Fig. 67 CLUTCH PACK AND LOWER SIDE GEAR
1 - DIFFERENTIAL CASE
2 - SIDE GEAR AND CLUTCH PACK
3 - 82 REAR AXLE - 198RBIWJ
DIFFERENTIAL-TRAC-LOC (Continued)

(8) Install anewcollapsible preload spacer on pin-
ion shaft and install pinion gear in the housing (Fig.
84).
(9) Install yoke with Installer C-3718 and Spanner
Wrench 6958 (Fig. 85).
(10) Install the yoke washer and a new nut on the
pinion gear and tighten the pinion nut until there is
zero bearing end-play.
(11) Tighten the nut to 271 N´m (200 ft. lbs.).
CAUTION: Never loosen pinion gear nut to decrease
pinion rotating torque and never exceed specified
preload torque. If preload torque or rotating torque
is exceeded a new collapsible spacer must be
installed.
(12) Using Spanner Wrench 6958 and a torque
wrench set at 474 N´m (350 ft. lbs.), (Fig. 86) slowly
tighten the nut in 6.8 N´m (5 ft. lbs.) increments
until the rotating torque is achieved. Measure the
rotating torque frequently to avoid over crushing the
collapsible spacer (Fig. 87).
NOTE: If more than 474 N´m (350 ft. lbs.) torque is
required to crush the collapsible spacer, the spacer
is defective and must be replaced.(13) Check bearing rotating torque with a inch
pound torque wrench (Fig. 87). The pinion gear rotat-
ing torque should be:
²Original Bearings: 1 to 2.25 N´m (10 to 20 in.
lbs.).
²New Bearings: 1.7 to 3.9 N´m (15 to 35 in. lbs.).
(14) Invert the differential case and start two ring
gear bolts. This will provide case-to-ring gear bolt
hole alignment.
Fig. 84 COLLAPSIBLE SPACER
1 - COLLAPSIBLE SPACER
2 - SHOULDER
3 - PINION GEAR
4 - DEPTH SHIM
5 - REAR BEARING
Fig. 85 PINION YOKE INSTALLER
1 - INSTALLER
2 - PINION YOKE
Fig. 86 PINION NUT
1 - SPANNER WRENCH
2 - PIPE
3 - TORQUE WRENCH
3 - 88 REAR AXLE - 198RBIWJ
PINION GEAR/RING GEAR (Continued)