Oil JEEP GRAND CHEROKEE 2002 WJ / 2.G Service Manual

NOTE: If more than 380 N´m (280 ft. lbs.) torque is
required to crush the collapsible spacer, the spacer
is defective and must be replaced.
(7) Check rotating torque with an inch pound
torque wrench (Fig. 44). The rotating torque of the
pinion gear should be, the reading recorded during
removal plus an additional 0.56 N´m (5 in. lbs.).
(8)
Install propeller shaft with reference marks align.
(9) Install rear brake rotors and calipers.
(10) Add gear lubricant, if necessary.
(11) Install wheel and tire assemblies.
(12) Remove supports and lower vehicle.
DIFFERENTIAL
REMOVAL
(1) Raise and support vehicle.
(2) Remove fill hole plug from the differential
housing cover.
(3) Remove differential housing cover and drain
fluid.
(4) Clean the housing cavity with flushing oil, light
engine oil or lint free cloth.
NOTE: Do not use water, steam, kerosene or gaso-
line for cleaning.
(5) Remove axle shafts.(6)
Note the reference letters stamped on the bearing
caps and housing machined sealing surface (Fig. 45).
(7) Loosen the differential bearing cap bolts.
(8) Position Spreader W-129-B with Adapter Kit
6987B on differential locating holes (Fig. 46). Install
holddown clamps and tighten the turnbuckle finger-
tight.
Fig. 44 PINION ROTATING TORQUE
1 - TORQUE WRENCH
2 - PINION YOKE
Fig. 45 BEARING CAP REFERENCE
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
Fig. 46 SPREADER LOCATION
1 - DIFFERENTIAL HOUSING
2 - DOWEL
3 - SAFETY HOLD DOWN
4 - SPREADER
5 - TURNBUCKLE
WJREAR AXLE - 226RBA 3 - 115
COLLAPSIBLE SPACER (Continued)

DISASSEMBLY
(1) Remove pinion shaft lock screw (Fig. 50).
(2) Remove pinion shaft.
(3) Rotate differential side gears and remove dif-
ferential pinions and thrust washers (Fig. 51).
(4) Remove differential side gears and thrust
washers.
ASSEMBLY
(1) Install differential side gears and thrust wash-
ers.
(2) Install differential pinion gears and thrust
washers.
(3) Install the pinion mate shaft.
(4) Align hole in the pinion mate shaft with the
hole in the differential case and install the pinion
mate shaft lock screw.
(5) Lubricate all differential components with
hypoid gear lubricant.
INSTALLATION
NOTE: If replacement differential bearings or differ-
ential case are being installed, differential side
bearing shim requirements may change. Refer
Adjustments (Differential Bearing Preload and Gear
Backlash) to determine the proper shim selection.
(1) Position Spreader W-129-B with Adapter set
6987 on differential housing locating holes. Install
the holddown 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.
CAUTION: Never spread the housing over 0.38 mm
(0.015 in). If housing is over-spread, it could be dis-
torted or damaged.
(3) Spread housing enough to install the case in
the housing.
(4) Remove the dial indicator.
(5) Install differential case in housing (Fig. 52).
Verify differential bearing cups remain in position on
the bearings and preload shims are between the face
of the bearing cup and the housing. Tap the differen-
tial case to ensure bearings cups and shims are
seated in the housing.
CAUTION: On a Vari-lokTdifferential the oil feed
tube must be pointed at the bottom of the housing
(Fig. 53). If differential is installed with the oil feed
tube pointed at the top, the anti-rotation tabs will be
damaged.
(6) Install bearing caps in their original locations
(Fig. 54).
(7) Loosely install differential bearing cap bolts.
(8) Remove axle housing spreader.
(9) Tighten bearing cap bolts in a criss-cross pat-
tern to 77 N´m (57 ft. lbs.).
(10) Install the axle shafts.
Fig. 50 SHAFT LOCK SCREW
1 - LOCK SCREW
2 - PINION SHAFT
Fig. 51 DIFFERENTIAL GEARS
1 - THRUST WASHER
2 - SIDE GEAR
3 - DIFFERENTIAL PINION
WJREAR AXLE - 226RBA 3 - 117
DIFFERENTIAL (Continued)

(11) Apply a 6.35mm (1/4 in.) bead of red Mopar
Silicone Rubber Sealant or equivalent to the housing
cover (Fig. 55).
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.
Fig. 52 SPREADER LOCATION
1 - DIFFERENTIAL HOUSING
2 - DOWEL
3 - SAFETY HOLD DOWN
4 - SPREADER
5 - TURNBUCKLE
Fig. 53 VARI-LOK
1 - ANTI-ROTATION TAB
2 - OIL FEED TUBE
Fig. 54 BEARING CAP REFERENCE
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
Fig. 55 DIFFERENTIAL COVER - TYPICAL
1 - COVER
2 - SEALANT
3 - SEALANT BEAD
3 - 118 REAR AXLE - 226RBAWJ
DIFFERENTIAL (Continued)

(9) Remove pinion yoke from pinion shaft with
Remover C-452 and Wrench C-3281 (Fig. 73).
(10) Remove pinion gear from housing (Fig. 74).(11) Remove pinion seal with Remover 7794-A and
a slide hammer (Fig. 75).
(12) Remove oil slinger, if equipped, and front pin-
ion bearing.
(13) Remove the front pinion bearing cup with
Remover D-103 and Handle C-4171 (Fig. 76).
Fig. 73 Pinion Yoke Remover
1 - FLANGE WRENCH
2 - YOKE
3 - YOKE PULLER
Fig. 74 Pinion Gear
1 - RAWHIDE HAMMER
Fig. 75 Pinion Seal Remover
1 - REMOVER
2 - SLIDE HAMMER
3 - PINION SEAL
Fig. 76 Front Pinion Bearing Cup
1 - REMOVER
2 - HANDLE
WJREAR AXLE - 226RBA 3 - 125
PINION GEAR/RING GEAR (Continued)

(14) Remove rear bearing cup from housing (Fig.
77) with Remover C-4307 and Handle C-4171.
(15) Remove collapsible preload spacer (Fig. 78).
(16) Remove rear bearing from the pinion with
Puller/Press C-293-PA and Adapters C-293-42 (Fig.
79).
(17) Remove depth shims from the pinion gear
shaft and record shim thickness.
INSTALLATION
NOTE: A pinion depth shim/oil slinger is placed
between the rear pinion bearing cone and the pin-
ion head to achieve proper ring gear and pinion
mesh. If ring gear and pinion are reused, the pinion
depth shim/oil slinger should not require replace-
ment. Refer to Adjustment (Pinion Gear Depth) to
select the proper thickness shim/oil slinger if ring
and pinion gears are replaced.
Fig. 77 Rear Pinion Bearing Cup
1 - REMOVER
2 - HANDLE
Fig. 78 Collapsible Spacer
1 - COLLAPSIBLE SPACER
2 - SHOULDER
3 - PINION GEAR
4 - DEPTH SHIM
5 - REAR BEARING
Fig. 79 Rear Pinion Bearing Puller
1 - PULLER
2 - VISE
3 - ADAPTERS
4 - PINION GEAR SHAFT
3 - 126 REAR AXLE - 226RBAWJ
PINION GEAR/RING GEAR (Continued)

(1) Apply Mopar Door Ease or equivalent lubricant
to outside surface of pinion bearing cups.
(2) Install pinion rear bearing cup with Installer
C-4308 and Driver Handle C-4171 (Fig. 80) and ver-
ify cup is seated.
(3) Install pinion front bearing cup with Installer
D-129 and Handle C-4171 (Fig. 81) and verify cup is
seated.(4) Install pinion front bearing and oil slinger, if
equipped.
(5) Apply a light coating of gear lubricant on the
lip of pinion seal. Install seal with an appropriate
(Fig. 82).
(6) Install depth shim on the pinion gear.
(7) Install rear bearing on the pinion gear with
Installer 6448 and a press (Fig. 83).
Fig. 80 Rear Pinion Bearing Cup
1 - INSTALLER
2 - HANDLE
Fig. 81 FRONT PINION BEARING CUP
1 - INSTALLER
2 - HANDLE
Fig. 82 PINION SEAL INSTALLER
1 - HANDLE
2 - INSTALLER
Fig. 83 REAR PINION BEARING
1 - PRESS
2 - INSTALLER
3 - PINION GEAR
4 - PINION BEARING
WJREAR AXLE - 226RBA 3 - 127
PINION GEAR/RING GEAR (Continued)

(13) Check bearing rotating torque with a inch
pound torque wrench (Fig. 87). The pinion gear rotat-
ing torque should be:
²
Original Bearings: 1 to 2.25 N´m (10 to 20 in. lbs.).
²New Bearings: 2.8 to 4 N´m (25 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.
(15) Invert the differential case in the vise.
(16) Installnewring gear bolts and alternately
tighten to 129-142 N´m (95-105 ft. lbs.) (Fig. 88).
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.
(17) Install differential in housing.
CAUTION: When installing a Vari-lokTdifferential
(Fig. 89), the oil feed tube must point to the bottom
of the housing. If differential is installed with the oil
feed tube pointed toward the top, the anti-rotation
tabs will be damaged.
(18)
Verify differential bearing preload, gear mesh
and contact pattern. Refer to Ajustments for procedure.
(19) Install differential cover and fill with gear
lubricant.(20) Install the propeller shaft with the reference
marks aligned.
(21) Remove supports and lower vehicle.
Fig. 87 PINION ROTATING TORQUE
1 - PINION YOKE/COMPANION FLANGE
2 - INCH POUND TORQUE WRENCH
Fig. 88 RING GEAR
1 - TORQUE WRENCH
2 - RING GEAR BOLT
3 - RING GEAR
4 - CASE
Fig. 89 VARI-LOK
1 - ANTI-ROTATION TAB
2 - OIL FEED TUBE
WJREAR AXLE - 226RBA 3 - 129
PINION GEAR/RING GEAR (Continued)

Common causes of brake drag are:
²Parking brake partially applied.
²Loose/worn wheel bearing.
²Seized caliper.
²Caliper binding.
²Loose caliper mounting.
²Mis-assembled components.
²Damaged brake lines.
If brake drag occurs at the front, rear or all
wheels, the problem may be related to a blocked mas-
ter cylinder return port, faulty power booster (binds-
does not release) or the ABS system.
BRAKE FADE
Brake fade is usually a product of overheating
caused by brake drag. However, brake overheating
and resulting fade can also be caused by riding the
brake pedal, making repeated high deceleration stops
in a short time span, or constant braking on steep
mountain roads. Refer to the Brake Drag information
in this section for causes.
BRAKE PULL
Front brake pull condition could result from:
²Contaminated lining in one caliper
²Seized caliper piston
²Binding caliper
²Loose caliper
²Rusty caliper slide surfaces
²Improper brake shoes
²Damaged rotor
²Wheel alignment.
²Tire pressure.
A worn, damaged wheel bearing or suspension compo-
nent are further causes of pull. A damaged front tire
(bruised, ply separation) can also cause pull.
A common and frequently misdiagnosed pull condi-
tion is where direction of pull changes after a few
stops. The cause is a combination of brake drag fol-
lowed by fade at one of the brake units.
As the dragging brake overheats, efficiency is so
reduced that fade occurs. Since the opposite brake
unit is still functioning normally, its braking effect is
magnified. This causes pull to switch direction in
favor of the normally functioning brake unit.
An additional point when diagnosing a change in
pull condition concerns brake cool down. Remember
that pull will return to the original direction, if the
dragging brake unit is allowed to cool down (and is
not seriously damaged).
REAR BRAKE DRAG OR PULL
Rear drag or pull may be caused by improperly
adjusted park brake shoes or seized parking brake
cables, contaminated lining, bent or binding shoes or
improperly assembled components. This is particu-
larly true when only one rear wheel is involved.However, when both rear wheels are affected, the
master cylinder or ABS system could be at fault.
BRAKES DO NOT HOLD AFTER DRIVING THROUGH DEEP
WATER PUDDLES
This condition is generally caused by water soaked
lining. If the lining is only wet, it can be dried by
driving with the brakes very lightly applied for a
mile or two. However, if the lining is both soaked and
dirt contaminated, cleaning and or replacement will
be necessary.
BRAKE LINING CONTAMINATION
Brake lining contamination is mostly a product of
leaking calipers or worn seals, driving through deep
water puddles, or lining that has become covered with
grease and grit during repair. Contaminated lining
should be replaced to avoid further brake problems.
WHEEL AND TIRE PROBLEMS
Some conditions attributed to brake components
may actually be caused by a wheel or tire problem.
A damaged wheel can cause shudder, vibration and
pull. A worn or damaged tire can also cause pull.
NOTE: Propshaft angle can also cause vibration/
shudder.
Severely worn tires with very little tread left can
produce a grab-like condition as the tire loses and
recovers traction. Flat-spotted tires can cause vibra-
tion and generate shudder during brake operation.
Tire damage such as a severe bruise, cut, ply separa-
tion, low air pressure can cause pull and vibration.
BRAKE NOISES
Some brake noise is common on some disc brakes
during the first few stops after a vehicle has been
parked overnight or stored. This is primarily due to
the formation of trace corrosion (light rust) on metal
surfaces. This light corrosion is typically cleared from
the metal surfaces after a few brake applications
causing the noise to subside.
BRAKE SQUEAK/SQUEAL
Brake squeak or squeal may be due to linings that
are wet or contaminated with brake fluid, grease, or oil.
Glazed linings and rotors with hard spots can also con-
tribute to squeak. Dirt and foreign material embedded
in the brake lining will also cause squeak/squeal.
A very loud squeak or squeal is frequently a sign of
severely worn brake lining. If the lining has worn
through to the brake shoes in spots, metal-to-metal
contact occurs. If the condition is allowed to continue,
rotors may become so scored that replacement is nec-
essary.
5 - 4 BRAKES - BASEWJ
BRAKES - BASE (Continued)

ADJUSTABLE PEDAL SWITCH
REMOVAL
(1) Remove the steering column opening cover
(Fig. 2)(Refer to 23 - BODY/INSTRUMENT PANEL/
STEERING COLUMN OPENING COVER - REMOV-
AL).
(2) Disconnect the electrical connector from the
adjustable pedal switch.
(3) Remove the switch from the steering column
opening cover by squeezing the retaining clips
together and pushing the switch outwards (Fig. 3).
INSTALLATION
(1) Install the switch to the steering column open-
ing cover by pushing the switch inwards seating the
retaining clips to the steering column opening cover
(Fig. 3).
(2) Reconnect the electrical connector to the
adjustable pedal switch.
(3) Install the steering column opening cover (Fig.
2)(Refer to 23 - BODY/INSTRUMENT PANEL/
STEERING COLUMN OPENING COVER - INSTAL-
LATION).
BRAKE LINES
DESCRIPTION
Flexible rubber hose is used at both front brakes,
rear brakes and at the rear axle junction block. Dou-
ble walled steel tubing is used. Double inverted style
and ISO style flares are used on the brake lines.
DIAGNOSIS AND TESTING - BRAKE HOSES
AND LINES
Flexible rubber hose is used at both front and rear
brakes and at the rear axle junction block. Inspect
the hoses whenever the brake system is serviced, at
every engine oil change, or whenever the vehicle is in
for service.
Inspect the hoses for surface cracking, scuffing, or
worn spots. Replace any brake hose immediately if
the fabric casing of the hose is exposed due to cracks
or abrasions.
Also check brake hose installation. Faulty installa-
tion can result in kinked, twisted hoses, or contact
with the wheels and tires or other chassis compo-
nents. All of these conditions can lead to scuffing,
cracking and eventual failure.
The steel brake lines should be inspected periodi-
cally for evidence of corrosion, twists, kinks, leaks, or
other damage. Heavily corroded lines will eventually
rust through causing leaks. In any case, corroded or
damaged brake lines should be replaced.
Factory replacement brake lines and hoses are rec-
ommended to ensure quality, correct length and supe-
rior fatigue life. Care should be taken to make sure
that brake line and hose mating surfaces are clean
and free from nicks and burrs. Also remember that
right and left brake hoses are not interchangeable.
Use new copper gaskets at all caliper connections.
Be sure brake line connections are properly made
(not cross threaded) and tightened to recommended
torque.
Fig. 2 STEERING COLUMN OPENING COVER
REMOVAL/INSTALL
1 - INSTRUMENT PANEL TOP PAD
2 - STEERING COLUMN OPENING COVER
3 - SCREW (3)
Fig. 3 ADJUSTABLE PEDAL SWITCH
1 - RETAINING CLIPS
2 - ELECTRICAL CONNECTION
5 - 8 BRAKES - BASEWJ

ASSEMBLY
ASSEMBLY - FRONT DISC BRAKE CALIPER
CAUTION: Dirt, oil, and solvents can damage cali-
per seals. Insure assembly area is clean and dry.
(1) Lubricate caliper pistons, piston seals and pis-
ton bores with clean brake fluid.
(2) Install new piston seals into seal groove with
finger (Fig. 38).
NOTE: Verify seal is fully seated and not twisted.(3) Install new dust boot on caliper piston and seat
boot lip into piston groove (Fig. 39).
(4) Stretch boot rearward to straighten boot folds,
then move boot forward until folds snap into place.
(5) Install piston into caliper bore and press piston
down to the bottom of the caliper bore by hand or
with hammer handle (Fig. 40).
Fig. 37 Polishing Piston Bore
1 - SPECIAL HONE
2 - CALIPER
3 - PISTON BORE
Fig. 38 Piston Seal
1 - CALIPER
2 - PISTON BORE
3 - PISTON SEAL
Fig. 39 Dust Boot On Piston
1 - PISTON
2 - DUST BOOT
Fig. 40 Caliper Piston Installation
1 - CALIPER
2 - DUST BOOT
3 - PISTON
5 - 20 BRAKES - BASEWJ
DISC BRAKE CALIPERS (Continued)