1. ZJ FRONT SUSPENSION AND AXLE 2-1
FRONT SUSPENSION AND AXLE
CONTENTS
page page
AXLE NOISE/VIBRATION DIAGNOSIS . . . . . . . . 12 MODEL 30 AXLE AND TUBE AXLE (2WD) . . . . 16
AXLE SPECIFICATIONS . . . . . . . . . . . . . . . . . . . 40 TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . 40
FRONT SUSPENSION . . . . . . . . . . . . . . . . . . . . . 8 WHEEL ALIGNMENT . . . . . . . . . . . . . . . . . . . . . . 4
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1
GENERAL INFORMATION
FRONT SUSPENSION The link/coil suspension allows each wheel to adapt
The Grand Cherokee front suspension is a link/coil to different road surfaces without greatly affecting
design comprised of (Fig. 1); the opposite wheel. Wheels are attached to a hub/
• Drive axle (4WD), tube axle (2WD) bearings which bolts to the knuckles. The hub/bear-
• Track bar ing is not serviceable and is replaced as a unit.
• Stabilizer bar Steering knuckles pivot on replaceable ball studs at-
• Upper and lower suspension arms tached to the axle tube yokes.
• Coil springs The upper and lower suspension arms use bushings
• Dual-action shock absorbers to isolate road noise. The suspension arms are bolted
• Jounce bumpers to the frame and axle through the rubber bushings.
Fig. 1 Front Suspension
2. 2-2 FRONT SUSPENSION AND AXLE ZJ
The lower suspension arm uses cam bolts at the axle
to allow for caster and pinion angle adjustment. The
suspension arm travel is limited through the use of
jounce bumpers in compression and shocks absorbers
in rebound.
The coil springs control ride quality and maintain
proper ride height. The coil springs mount up in the
wheelhouse which is part of the unitized body
bracket. A rubber doughnut isolator is located be-
tween the top of the spring and the body. The bottom
of the spring seats on a axle pad and is retained with
a clip.
The shock absorbers dampen jounce and rebound
motion of the vehicle over various road conditions.
The top of the shock absorbers are bolted to the body.
The bottom of the shocks are bolted to the axle
brackets.
The stabilizer bar is used to control vehicle body
roll during turns. The spring steel bar helps to con-
trol the vehicle body in relationship to the suspen-
sion. The bar extends across the front underside of
the chassis and connects to the frame rails. Links are Fig. 2 Model 30 Differential Cover
connected from the bar to the axle brackets. Stabi-
• Ring gear (bolted to the differential case) rotates
lizer bar mounts are isolated by rubber bushings.
the case
The track bar is used to control front axle lateral
• Differential pinion gears (mounted on the pinion
movement. The bar is attached to a frame rail mate shaft in the case) rotate the side gears
bracket with a ball stud and isolated with a bushing • Side gears (splined to the axle shafts) rotate the
at the axle bracket. shafts
Suspension components which use rubber bushings During straight-ahead driving, the differential pin-
should be tightened at vehicle ride height. This will ion gears do not rotate on the pinion mate shaft. This
prevent premature failure of the bushing and main- occurs because input torque applied to the gears is
tain ride comfort. Bushings must never be lubricated. divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
FRONT DRIVE AXLE pinion mate shaft but do not rotate around it (Fig. 3).
The integral type housing, has the centerline of the When turning corners, the outside wheel must
pinion set below the centerline of the ring gear.
The axles are equipped with A.B.S. brake systems.
The A.B.S. tone rings are pressed onto the axle shaft
near the hub and knuckle. For additional information
on the A.B.S. system refer to Group 5, Brakes.
The Model 30 axle has the assembly part number
and gear ratio listed on a tag. The tag is attached to
the housing cover (Fig. 2). Build date identification
codes are stamped on the axle shaft tube cover side.
STANDARD DIFFERENTIAL OPERATION
The differential gear system divides the torque be-
tween the axle shafts. It allows the axle shafts to ro-
tate at different speeds when turning corners.
Each differential side gear is splined to an axle
shaft. The pinion gears are mounted on a pinion
mate shaft and are free to rotate on the shaft. The Fig. 3 Differential Operation—Straight-Ahead Driving
pinion gear is fitted in a bore in the differential case travel a greater distance than the inside wheel in or-
and is positioned at a right angle to the axle shafts. der to complete a turn. This difference must be com-
In operation, power flow occurs as follows: pensated for in order to prevent the wheels from
• Pinion gear rotates the ring gear scuffing and skidding through the turn. To accom-
3. ZJ FRONT SUSPENSION AND AXLE 2-3
plish this the differential allows the axle shafts to mounts in the same bracketry as does the four wheel
turn at unequal speeds (Fig. 4). In this instance, the drive front axle. The steering knuckles and hub bear-
input torque applied to the pinion gears is not di- ing assemblies are the same as used on the Model 30
vided equally. The pinion gears now rotate around drive axle.
the pinion mate shaft in opposite directions. This al-
lows the side gear and axle shaft attached to the out-
side wheel to rotate at a faster speed.
Fig. 4 Differential Operation—On Turns
TUBE AXLE (2WD VEHICLES)
The front axle used on two wheel drive vehicles is
Fig. 5 Front Axle—2WD Vehicles
a one-piece, tubular axle (Fig. 5). The tubular axle
4. 2-4 FRONT SUSPENSION AND AXLE ZJ
WHEEL ALIGNMENT
GENERAL INFORMATION camber. Incorrect camber will cause wear on the in-
Four wheel alignment involves the correct position- side or outside edge of the tire (Fig. 1).
ing of the wheels in relation to the vehicle. The posi- • TOE is the difference between the leading inside
tioning is accomplished through suspension and edges and trailing inside edges of the front tires (Fig.
steering linkage adjustments. An alignment is con- 1). Uneven wheel toe position cause’s unstable steer-
sidered essential for efficient steering, good direc- ing, uneven tire wear and steering wheel off-center.
tional stability and to minimize tire wear. The most The wheel toe position is the final front wheel align-
important measurements of an alignment are caster, ment adjustment.
camber toe and thrust angle. • THRUST ANGLE is the angle of the rear axle rel-
Routine inspection of the front suspension ative to the vehicle center line. If this angle is off the
and steering components is a good preventative vehicle may drift or wander.
maintenance practice. Inspection also helps to • STEERING AXIS INCLINATION ANGLE is mea-
ensure safe operation of the vehicle. sured in degrees. It is the angle that the steering
• CASTER is the forward or rearward tilt of the knuckles are tilted (Fig. 1). The inclination angle has
steering knuckle from vertical. Tilting the top of the a fixed relationship with the camber angle. It will not
knuckle forward provides negative caster. Tilting the
change except when a spindle or ball stud is dam-
top of the knuckle rearward provides positive caster.
aged or bent. The angle is not adjustable and the
Positive caster promotes directional stability. This
damaged component(s) must be replaced to correct
angle enables the front wheels to return to a straight
mis-alignment.
ahead position after turns (Fig. 1).
• CAMBER is the inward or outward tilt of the
CAUTION: Do not attempt to modify any suspen-
wheel relative to the center of the vehicle. Tilting the
sion or steering component by heating and bend-
top of the wheel inward provides negative camber.
ing.
Tilting the top of the wheel outward provides positive
Fig. 1 Wheel Alignment Angles
5. ZJ FRONT SUSPENSION AND AXLE 2-5
ALIGNMENT MEASUREMENTS AND
ADJUSTMENTS
Before each alignment reading the vehicle should
be jounced (rear first, then front). Grasp each
bumper at the center and jounce the vehicle up and
down three times. Always release the bumper in the
down position.
CAMBER
The wheel camber angle (Fig. 1) is preset. This an-
gle is not adjustable and cannot be altered.
CASTER
Check the caster of the front axle for correct angle
(fig. 1). Be sure the axle is not bent or twisted. Road
test the vehicle and observe the steering wheel re-
turn-to-center position. Low caster will cause poor
steering wheel returnability.
During the road test, turn the vehicle to both the
left and right. If the steering wheel returns to the
center position unassisted, the caster angle is correct.
Fig. 2 Cam Adjuster However, if steering wheel does not return toward
the center position unassisted, a low caster angle is
PRE-ALIGNMENT INSPECTION probable.
Before starting a front wheel alignment, the follow- Front aster can be adjusted by loosening and rotat-
ing inspection and necessary corrections must be
ing the cams on the lower suspension arm (Fig. 2).
completed.
Changing caster angle will also change the
(1) Tires with the same recommended air pressure,
front propeller shaft angle. The propeller shaft
size, and tread wear. Refer to Group 22, Wheels and
angle has priority over caster. Refer to Group
Tires for diagnosis information.
(2) Front wheel bearings for wear. 16, Propeller Shafts for additional information.
(3) Ball studs, steering linkage pivot points and
TOE POSITION
steering gear for looseness, roughness, binding or
The wheel toe position adjustment should be the fi-
wear. Refer to Group 19, Steering for additional in-
nal adjustment.
formation.
(4) Wheels for excessive radial, lateral runout and (1) Start the engine and turn wheels both ways be-
unbalance. Refer to Group 22, Wheels and Tires for fore straightening the steering wheel. Center and se-
diagnosis information. cure the steering wheel.
(5) Suspension components for wear and noise. (2) Loosen the adjustment sleeve clamp bolts (Fig.
Check components for correct torque. Refer to Groups 3).
2 and 3, Suspension and Axle for additional informa-
tion.
Fig. 3 Steering Linkage
6. 2-6 FRONT SUSPENSION AND AXLE ZJ
SUSPENSION AND STEERING SYSTEM DIAGNOSIS
7. ZJ FRONT SUSPENSION AND AXLE 2-7
ALIGNMENT SPECIFICATIONS
Fig. 4 Drag Link and Tie Rod Clamp Location
(3) Adjust the right wheel toe position with the same TOE-IN position as the right wheel. Position
drag link. Turn the sleeve until the right wheel is at the clamp bolts as shown (Fig. 4) and tighten to 27
the correct positive TOE-IN position. Position the N⅐m (20 ft. lbs.) torque. Make sure the toe setting
clamp bolts as shown (Fig. 4) and tighten to 49 N⅐m does not change during clamp tightening.
(36 ft. lbs.) torque. Make sure the toe setting does (5) Verify the right toe setting.
not change during clamp tightening.
(4) Adjust the left wheel toe position with the tie
rod. Turn the sleeve until the left wheel is at the
8. 2-8 FRONT SUSPENSION AND AXLE ZJ
FRONT SUSPENSION
INDEX
page page
Axle Bushing Replacement . . . . . . . . . . . . . . . . . . . 9 Spring and Shock Diagnosis . . . . . . . . . . . . . . . . . 10
Coil Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Stabilizer Bar . . . . . . . . . . . .................. 8
Lower Suspension Arm . . . . . . . . . . . . . . . . . . . . . . 9 Track Bar . . . . . . . . . . . . . . .................. 8
Service Information . . . . . . . . . . . . . . . . . . . . . . . . . 8 Upper Suspension Arm . . . . .................. 9
Shock Absorber . . . . . . . . . . . . . . . . . . . . . . . . . . 10
SERVICE INFORMATION
Periodic lubrication of the front suspension (steer-
ing) system components is required. Refer to Group
0, Lubrication And Maintenance for the recom-
mended maintenance schedule.
CAUTION: Suspension components with rubber
bushings should be tightened with the vehicle at
normal height. It is important to have the springs
supporting the weight of the vehicle when the fas-
teners are torqued. If springs are not at their normal
ride position, vehicle ride comfort could be affected
and premature bushing wear may occur. Rubber
bushings must never be lubricated.
TRACK BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the cotter pin and nut from the ball
stud end at the frame rail bracket (Fig. 1).
A puller tool may be necessary to separate the
ball stud from the frame rail bracket.
(3) Remove the bolt and flag nut from the axle
shaft tube bracket (Fig. 1). Remove the track bar.
INSTALLATION Fig. 1 Track Bar
(1) Install the track bar at axle tube bracket.
STABILIZER BAR
Loosely install the retaining bolt and flag nut (Fig.
1). REMOVAL
(2) It may be necessary to pry the axle assembly (1) Raise and support the vehicle.
over to install the track bar at the frame rail. Install (2) Disconnect the stabilizer bar links from the
track bar at the frame rail bracket (Fig. 1). Install axle brackets (Fig. 2).
the retaining nut on the stud. (3) Disconnect the stabilizer bar from the links.
(3) Remove the supports and lower the vehicle. (4) Disconnect the stabilizer bar clamps from the
(4) Tighten the bolt at the axle shaft tube bracket frame rails. Remove the stabilizer bar.
to 75 N⅐m (55 ft. lbs.) torque.
(5) Tighten the ball stud nut to 81 N⅐m (60 ft. lbs.) INSTALLATION
torque. Install a new cotter pin. (1) Position the stabilizer bar on the frame rail and
(6) Check alignment if a new track bar was in- install the clamps and bolts. Ensure the bar is cen-
stalled. tered with equal spacing on both sides. Tighten the
bolts to 54 N⅐m (40 ft. lbs.).
9. ZJ FRONT SUSPENSION AND AXLE 2-9
INSTALLATION
(1) Position the upper suspension arm at the axle
and frame rail (Fig. 3).
(2) Install the bolts and finger tighten the nuts
(Fig. 3).
(3) Remove the supports and lower the vehicle.
(4) Tighten the nut at the axle and frame bracket
to 75 N⅐m (55 ft. lbs.) torque.
AXLE BUSHING REPLACEMENT
(1) Remove the upper suspension arm from axle.
Refer to Upper Suspension Arm Removal in this
Group.
(2) Insert Spacer 7932-3 (J-35581-3) around the
bushing in the axle bracket ears (Fig. 4).
(3) Assemble and install Bushing Removal/In-
staller (Fig. 4).
(4) Remove the bushing by tightening the hex-head
on Long Nut.
Fig. 2 Stabilizer Bar
(2) Install the links and grommets onto the stabi-
lizer bar and axle brackets (Fig. 2). Tighten the nut
at the connecting links at the axle bracket to 95 N⅐m
(70 ft. lbs.) torque.
(3) Tighten the stabilizer bar to connecting link
nut to 36 N⅐m (27 ft. lbs.) torque.
(4) Remove the supports and lower the vehicle.
UPPER SUSPENSION ARM
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the upper suspension arm nut and bolt
at the axle bracket (Fig. 3).
(3) Remove the nut and bolt (Fig. 3) at the frame
rail and remove the upper suspension arm.
Fig. 4 Axle Bracket Bushing Removal
For two-wheel drive axles and right side on
Model 30 axle, do not remove Spacer 7932-3 (J-
35581-3) at this time.
(5) Position the new bushing on Installer.
(6) Install the bushing by tightening the hex-head
on Long Nut (Fig. 5). Remove Spacer 7932-3 (J-
35581-3).
(7) Install the upper suspension arm to axle. Refer
to Upper Suspension Arm Installation in this Group.
LOWER SUSPENSION ARM
REMOVAL
Fig. 3 Upper and Lower Suspension Arms (1) Raise and support the vehicle.
10. 2 - 10 FRONT SUSPENSION AND AXLE ZJ
INSTALLATION
(1) Position the lower suspension arm at the axle
bracket and frame rail bracket.
(2) Install the rear bolts and finger tighten the
new nuts (Fig. 6).
(3) Install a new cam bolt, cam and new nut in the
axle. Re-align the reference marks.
(4) Install the bolts and finger tighten the new
nuts (Fig. 6).
(5) Lower the vehicle.
(6) Tighten the front and rear nuts to 115 N⅐m (85
ft. lbs.) torque.
(7) Check the alignment if new parts were in-
stalled.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber can be pro-
duced if movement between the rubber bushings and
the metal occurs. This noise can usually be stopped
by tightening the attaching nuts. If the squeak noise
persists, inspect for damaged and worn bushings,
Fig. 5 Axle Bracket Bushing Installation and attaching components. Repair as necessary.
(2) Paint or scribe alignment marks on the cam ad- The shock absorbers are not refillable or adjust-
justers and suspension arm for installation reference able. If a malfunction occurs, the shock absorber
(Fig. 6). must be replaced. To test a shock absorber, hold it in
an upright position and force the piston into and out
of the cylinder four or five times. The action through-
out each stroke should be smooth and even.
SHOCK ABSORBER
REMOVAL
(1) Remove the nut, retainer and grommet from
the upper stud in the engine compartment (Fig. 7).
(2) Remove the lower nuts and bolts from the axle
bracket (Fig. 7). Remove the shock absorber.
INSTALLATION
(1) Position the lower retainer and grommet on the
upper stud. Insert the shock absorber through the
shock tower hole.
(2) Install the lower bolts and nuts. Tighten nuts
to 28 N⅐m (250 in. lbs.) torque.
(3) Install the upper grommet and retainer on the
stud in the engine compartment. Install the nut and
tighten to 23 N⅐m (17 ft. lbs.) torque.
Fig. 6 Cam Adjuster COIL SPRING
(3) Remove the lower suspension arm nut, cam REMOVAL
and cam bolt from the axle (Fig. 3). (1) Raise and support the vehicle. Position a hy-
(4) Remove the nut and bolt from the frame rail draulic jack under the axle to support it.
bracket and remove the lower suspension arm (Fig. (2) Paint or scribe alignment marks on the cam ad-
6). justers and axle bracket for installation reference
(Fig. 6).
(3) Mark and disconnect the front propeller shaft
from the axle.
11. ZJ FRONT SUSPENSION AND AXLE 2 - 11
(5) Disconnect the stabilizer bar link and shock ab-
sorber from the axle.
(6) Disconnect the track bar from the frame rail
bracket.
(7) Disconnect the drag link from the pitman arm.
(8) Lower the axle until the spring is free from the
upper mount. Remove the coil spring retainer bolt
and remove the spring.
(9) Remove the jounce bumper if necessary from
the upper spring mount (Fig. 7).
INSTALLATION
(1) Install the jounce bumper on the upper spring
mount. Tighten the bolts to 42 N⅐m (31 ft. lbs.)
torque (Fig. 7).
(2) Position the coil spring on the axle pad. Install
the spring retainer and bolt.
(3) Raise the axle into position until the spring
seats in the upper mount.
(4) Connect the stabilizer bar links and shock ab-
sorbers to the axle bracket. Connect the track bar to
the frame rail bracket.
(5) Install the lower suspension arm to the axle.
(6) Install the front propeller shaft to the axle.
(7) Install drag link to pit man arm.
(8) Remove the supports and lower the vehicle.
(9) Tighten all suspension components to proper
Fig. 7 Coil Spring & Shock Absorber torque.
(4) Remove the lower suspension arm nut, cam
and cam bolt from the axle (Fig. 3).
12. 2 - 12 FRONT SUSPENSION AND AXLE ZJ
AXLE NOISE/VIBRATION DIAGNOSIS
INDEX
page page
Driveline Snap . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Low Speed Knock . . . . . . . . . . . . . . . . . . . . . . . . . 13
Gear and Bearing Noise . . . . . . . . . . . . . . . . . . . . 12 Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
General Information . . . . . . . . . . . . . . . . . . . . . . . 12
GENERAL INFORMATION Excessive bearing preload may not be noisy. This
Axle bearing problem conditions are usually caused condition will cause high temperature which can re-
by: sult in bearing failure.
• Insufficient or incorrect lubricant
• Foreign matter/water contamination GEAR AND BEARING NOISE
• Incorrect bearing preload torque adjustment
• Incorrect backlash ( to tight)
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
When serviced, the bearings must be cleaned thor-
cant. Incorrect backlash, tooth contact, or worn/dam-
oughly. They should be dried with lint free shop tow-
aged gears can cause noise.
els. Never dry bearings with compressed air.
Gear noise usually happens at a specific speed
This will overheat them and brinell the bearing
range. The range is 30 to 40 mph, or above 50 mph.
surfaces. This will result in noisy operation af-
The noise can also occur during a specific type of
ter repair.
driving condition. These conditions are acceleration,
Axle gear problem conditions are usually the result
deceleration, coast, or constant load.
of:
When road testing, accelerate the vehicle to the
• Insufficient lubrication
• Incorrect or contaminated lubricant speed range where the noise is the greatest. Shift out
• Overloading (excessive engine torque) of gear and coast through the peak noise range. If
• Exceeding vehicle weight capacity the noise stops or changes greatly, check for insuffi-
• Incorrect clearance or backlash adjustment cient lubricant. Incorrect ring gear backlash, or gear
Insufficient lubrication is usually the result of a damage can cause noise changes.
housing cover leak. It can also be from worn axle Differential side and pinion gears can be checked
shaft or pinion gear seals. Check for cracks or porous by turning the vehicle. They usually do not cause
areas in the housing or tubes. noise in straight ahead driving. These gears are
Using the wrong lubricant will cause overheating loaded during vehicle turns. If noise does occur dur-
and gear failure. Gear tooth cracking and bearing ing vehicle turns, the side or pinion gears could be
spalling are indicators of this. worn or damaged. A worn pinion gear mate shaft can
Axle component breakage is most often the result also cause a snapping or a knocking noise.
of:
• Severe overloading BEARING NOISE
• Insufficient lubricant The axle shaft, differential and pinion gear bear-
• Incorrect lubricant ings can all produce noise when worn or damaged.
• Improperly tightened components Bearing noise can be either a whining, or a growling
Common causes of overloading is from full throttle sound.
acceleration. Overloading happens when towing Pinion gear bearings have a constant pitch noise.
heavier than recommended loads. Component break- This noise changes only with vehicle speed. Pinion
age can occur when the wheels are spun excessively. bearing noise will be higher because it rotates at a
Insufficient or incorrect lubricants contribute to faster rate. Drive the vehicle and load the differen-
breakage through overheating. Loose differential tial. If bearing noise occurs the pinion rear bearing is
components can also cause breakage. the source of the noise. If the bearing noise is heard
Incorrect bearing preload or gear backlash will not during a coast, front bearing is the source.
result in component breakage. This will cause accel- Worn, damaged differential bearings usually pro-
erated wear and contribute to early failure. Mis-ad- duce a low pitch noise. Differential bearing noise is
justment will produce noise. If a mis-adjustment similar to pinion bearing. The pitch of differential
condition is not corrected, component failure can re- bearing noise is also constant and varies only with
sult. vehicle speed.
13. ZJ FRONT SUSPENSION AND AXLE 2 - 13
Axle shaft bearings produce noise and vibration • Bent axle shaft
when worn or damaged. The noise generally changes Check for loose or damaged front end components
when the bearings are loaded. Road test the vehicle. or engine/transmission mounts. These components
Turn the vehicle sharply to the left and to the right. can contribute to what appears to be a rear end vi-
This will load the bearings and change the noise bration. Do not overlook engine accessories, brackets
level. Where axle bearing damage is slight, the noise and drive belts.
is usually not noticeable at speeds above 30 mph. All driveline components should be examined be-
fore starting any repair.
LOW SPEED KNOCK Refer to Group 22, Wheels And Tires for additional
Low speed knock is generally caused by a worn U- information.
joint or by worn side gear thrust washers. A worn
pinion gear shaft bore will also cause low speed DRIVELINE SNAP
knock. A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged), can be caused by:
VIBRATION • High engine idle speed
Vibration at the rear of the vehicle is usually • Loose engine/transmission/transfer case mounts
caused by a: • Worn U-joints
• Damaged drive shaft • Loose spring mounts
• Missing drive shaft balance weight • Loose pinion gear nut and yoke
• Worn, out-of-balance wheels • Excessive ring gear backlash
• Loose wheel lug nuts • Excessive differential side gear-to-case clearance
• Worn U-joint The source of a snap or a clunk noise can be deter-
• Loose spring U-bolts mined with the assistance of a helper. Raise the ve-
• Loose/broken springs hicle on a hoist with the wheels free to rotate.
• Damaged axle shaft bearings Instruct the helper to shift the transmission into
• Loose pinion gear nut gear. Listen for the noise, a mechanics stethoscope is
• Excessive pinion yoke run out helpful in isolating the source of a noise.
14. 2 - 14 FRONT SUSPENSION AND AXLE ZJ
SERVICE DIAGNOSIS
15. ZJ FRONT SUSPENSION AND AXLE 2 - 15
SERVICE DIAGNOSIS (CONT’D)
16. 2 - 16 FRONT SUSPENSION AND AXLE ZJ
MODEL 30 AXLE AND TUBE AXLE (2WD)
INDEX
page page
Axle Bushing Replacement . . . . . . . . . . . . . . . . . . 26 Drive Axle Assembly Replacement . . . . . . . . . . . . . 16
Axle Shaft Oil Seals . . . . . . . . . . . . . . . . . . . . . . . 26 Final Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Axle Shaft— Cardan U-Joint . . . . . . . . . . . . . . . . . 20 General Information . . . . . . . . . . . . . . . . . . . . . . . 16
Axle Shaft— CV-Joint . . . . . . . . . . . . . . . . . . . . . . 21 Hub Bearing and Axle Shaft . . . . . . . . . . . . . . . . . 19
Backlash and Contact Pattern Analysis . . . . . . . . . 37 Lubricant Change . . . . . . . . . . . . . . . . . . . . . . . . . 17
Cleaning/Inspection . . . . . . . . . . . . . . . . . . . . . . . . 29 Lubricant Specifications . . . . . . . . . . . . . . . . . . . . . 16
Differential and Pinion Measurement . . . . . . . . . . . 32 Pinion Gear Assembly/Installation . . . . . . . . . . . . . 33
Differential Assembly . . . . . . . . . . . . . . . . . . . . . . . 30 Pinion Gear Depth Information . . . . . . . . . . . . . . . 30
Differential Disassembly . . . . . . . . . . . . . . . . . . . . 26 Pinion Removal/Disassembly . . . . . . . . . . . . . . . . . 28
Differential Installation . . . . . . . . . . . . . . . . . . . . . . 36 Pinion Shaft Seal Replacement . . . . . . . . . . . . . . . 18
Differential Removal . . . . . . . . . . . . . . . . . . . . . . . 26
Differential Shim Pack Measurement and Steering Knuckle and Ball Studs . . . . . . . . . . . . . . 24
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
GENERAL INFORMATION LUBRICANT SPECIFICATIONS
The housing for Model 30 front axles consists of an Multi-purpose, hypoid gear lubricant should be
iron center casting with tubes on each side. The used for Model 30 axles. The lubricant should have
tubes are pressed into and welded to the differential MIL-L-2105C and API GL 5 quality specifications.
housing. MOPAR Hypoid Gear Lubricant conforms to both of
The integral type housing, hypoid gear design has these specifications.
the centerline of the pinion set below the centerline • The factory fill for the Model 30 axle is SAE Ther-
of the ring gear. mally Stable 80W-90 gear lubricant
The axle has a vent used to relieve internal pres- • The factory installed lubricant quantity for the
sure caused by lubricant vaporization and internal NON-DISCONNECT TYPE AXLE is 40Ϯ1 fluid oz.
expansion. Refer to Group 0, Lubrication and Maintenance for
The axles are equipped with semi-floating axle additional information.
shafts, meaning that loads are supported by the hub
bearings. The axle shafts are retained by nuts at the CAUTION: If axle is submerged in water, lubricant
hub bearings. The hub bearings are bolted to the must be replaced immediately to avoid contamina-
steering knuckle at the outboard end of the axle tube tion.
yoke. The hub bearings are serviced as an assembly.
The axles are equipped with ABS brake sensors.
DRIVE AXLE ASSEMBLY REPLACEMENT
The sensors are attached to the knuckle assemblies
and tone rings are pressed on the axle shaft. Use REMOVAL
care when removing axle shafts as NOT to dam- (1) Raise vehicle and position support stands un-
age the tone wheel or the sensor. der the frame rails behind the lower suspension arm
The stamped steel cover provides a means for in- brackets.
spection and servicing the differential. (2) Remove the front wheels.
The Model 30 axle has the assembly part number (3) Remove the brake components and ABS brake
and gear ratio listed on a tag. The tag is attached to sensor (if equipped). Refer to Group 5—Brakes.
the housing cover. Build date identification codes are (4) On 4WD vehicles, disconnect the axle vent
stamped on the axle shaft tube cover side. hose.
The differential case is a one piece design. The dif- (5) On 4WD vehicles, mark the drive shaft yoke
ferential pinion mate shaft is retained with a roll and axle pinion yoke for alignment reference. Discon-
pin. Differential bearing preload and ring gear back- nect the drive shaft from the axle.
lash is adjusted by the use of shims. The shims are (6) Disconnect the stabilizer bar link at the axle
located between the differential bearing cones and bracket.
case. Pinion bearing preload is set and maintained by (7) Disconnect the shock absorbers from axle
the use of a collapsible spacer. bracket.
(8) Disconnect the track bar from the axle bracket.
17. ZJ FRONT SUSPENSION AND AXLE 2 - 17
(9) Disconnect the tie rod and drag link from the (15) Tighten the upper suspension arm nuts to 75
steering knuckle. Disconnect the steering dampener N⅐m (55 ft. lbs.) torque. Tighten the lower suspension
from the axle bracket. arm nuts to 115 N⅐m (85 ft. lbs.) torque.
(10) Support the axle with a hydraulic jack under (16) Tighten the track bar bolt at the axle bracket
the differential. to 75 N⅐m (55 ft. lbs.) torque.
(11) Disconnect the upper and lower suspension (17) Check the front wheel alignment.
arms from the axle bracket.
(12) Lower the jack enough to remove the axle. LUBRICANT CHANGE
The coil springs will drop with the axle. The gear lubricant will drain quicker if the vehicle
(13) Remove the coil springs from the axle bracket. has been recently driven.
(1) Raise and support the vehicle.
INSTALLATION (2) Remove the lubricant fill hole plug from the dif-
ferential housing cover.
CAUTION: Suspension components with rubber (3) Remove the differential housing cover and
bushings should be tightened with the vehicle at drain the lubricant from the housing.
normal height. It is important to have the springs (4) Clean the housing cavity and oil channels with
supporting the weight of the vehicle when the fas- a flushing oil, light engine oil or lint free cloth. Do
teners are torqued. If springs are not at their normal not use water, steam, kerosene or gasoline for
ride position, vehicle ride comfort could be affected cleaning.
and premature bushing wear may occur. Rubber (5) Remove the sealant from the housing and cover
bushings must never be lubricated. surfaces. Use solvent to clean the mating surfaces.
(6) Apply a bead of MOPAR Silicone Rubber Seal-
(1) Install the springs, retainer clip and bolts. ant to the housing cover (Fig. 1). Allow the sealant
(2) Support the axle on a hydraulic jack under the to cure for a few minutes.
differential. Position the axle under the vehicle.
(3) Raise the axle with a floor jack and align it
with the spring pads.
(4) Position the upper and lower suspension arm at
the axle bracket. Install bolts and nuts finger
tighten.
(5) Connect the track bar to the axle bracket and
install the bolt. Do not tighten at this time.
It is important that the springs support the
weight of the vehicle when the track bar is con-
nected. If the springs are not at their usual po-
sition, the vehicle ride comfort could be
affected.
(6) Install the shock absorber and tighten nuts to
27 N⅐m (20 ft. lbs.) torque.
(7) Install the stabilizer bar link to the axle
bracket. Tighten the nut to 95 N⅐m (70 ft. lbs.)
torque.
(8) Install the drag link and tie rod to the steering
knuckles and tighten the nuts to 47 N⅐m (35 ft. lbs.)
torque. Install the steering dampener to the axle
bracket and tighten the nut to 75 N⅐m (55 ft. lbs.)
torque.
(9) Install the brake components and ABS brake Fig. 1 Typical Housing Cover With Sealant
sensor (if equipped). Refer to Group 5—Brakes. Install the housing cover within 5 minutes af-
(10) On 4WD vehicles, connect the vent hose to the ter applying the sealant. If not installed the
tube fitting. sealant must be removed and another bead ap-
(11) On 4WD vehicles, align the reference marks plied.
and connect the drive shaft to the axle yoke. Tighten (7) Install the cover and any identification tag.
the U-joint clamp bolts to 19 N⅐m (14 ft. lbs.) torque. Tighten the cover bolts in a criss-cross pattern to 41
(12) Check differential lubricant and add if neces- N⅐m (30 ft. lbs.) torque.
sary. (8) Refill the differential with MOPAR Hypoid
(13) Install the wheel and tire. Gear Lubricant to the bottom of fill plug hole.
(14) Remove the supports and lower the vehicle. (9) Install the fill hole plug and lower the vehicle.
18. 2 - 18 FRONT SUSPENSION AND AXLE ZJ
PINION SHAFT SEAL REPLACEMENT
REMOVAL
(1) Raise and support the vehicle.
(2) Remove wheel and tire assemblies
(3) Mark the propeller shaft yoke and pinion yoke
for installation alignment reference.
(4) Remove the propeller shaft from the yoke.
(5) Rotate the pinion gear three or four times.
Make sure brakes are not dragging during this
procedure.
(6) Measure the amount of torque (in Newton-
meters or inch-pounds) necessary to rotate the pinion
gear with a torque wrench. Note the torque for in-
stallation reference. It must be known to properly
adjust the pinion gear bearing preload torque
Fig. 3 Seal Removal
after seal installation.
(7) Remove the pinion yoke nut and washer. Use
Remover C-452 and Wrench C-3281 to remove the
pinion yoke (Fig. 2).
(8) Mark the positions of the yoke and pinion gear
for installation alignment reference.
Fig. 2 Pinion Yoke Removal Fig. 4 Pinion Seal Installation
(9) Use Remover 7794A and slide hammer to re- on the pinion shaft will have to be replaced. The
move the pinion gear seal (Fig. 3). bearing preload torque will be re-adjusted after-
ward.
INSTALLATION
(1) Apply a light coating of gear lubricant on the (4) Install a socket and inch-pound torque wrench
lip of pinion seal. Install seal with Installer D-163 on the pinion nut.
and Handle C-4171 (Fig. 4). (5) Rotate the shaft with the torque wrench and
(2) Align the installation reference marks and in- note the torque.
stall yoke on the pinion gear with Installer W-162D. The required preload is equal to amount re-
(3) Install a new nut on the pinion gear. Tighten corded during removal plus 0.56 N⅐m (5 in. lbs.).
the nut only enough to remove the shaft end The used bearing preload torque must never
play. exceed 2.25 N⅐m (20 in. lbs.)
(6) Use Flange Wrench C-3281 to retain the yoke
CAUTION: Exercise care during the bearing preload and shaft (Fig. 5). Tighten the shaft nut in very
torque adjustment. Do not over-tighten, or loosen small increments. Vehicles with Type 3 propeller
and then re-tighten the nut. Do not exceed the bear- shaft use Flange Wrench C-3281 with 2 bolts in-
ing preload torque. The collapsible preload spacer stalled into the flange (Fig. 6).
19. ZJ FRONT SUSPENSION AND AXLE 2 - 19
Fig. 6 Tightening Pinion Nut with Type 3 Shaft
HUB BEARING AND AXLE SHAFT
REMOVAL
(1) Raise and support the vehicle.
Fig. 5 Tightening Pinion Nut (2) Remove the wheel and tire assembly.
(3) Remove the brake components from the axle,
(7) Continue tightening the shaft nut in small in- refer to Group 5, Brakes.
crements until the correct bearing preload torque is (4) Remove the cotter pin, nut retainer and axle
attained. Tighten the pinion shaft nut: hub nut (Fig. 7).
• No less than 217 N⅐m (160 ft. lbs.) torque (5) Remove the hub to knuckle bolts (Fig. 7). Re-
• No greater than 352 N⅐m (260 ft. lbs.) torque move the hub from the steering knuckle and axle
(8) Align the installation reference marks and at- shaft.
tach the propeller shaft to the yoke. (6) Remove the disc brake rotor shield from the
(9) Add API grade GL 5 hypoid gear lubricant to bearing carrier (Fig. 7).
the differential housing, if necessary. (7) On 4WD vehicles, remove the axle shaft
(10) Install wheel and tire assemblies from the housing. Avoid damaging the axle
(11) Lower the vehicle. shaft oil seals in the differential.
Fig. 7 Hub, Knuckle and Axle Shaft
20. 2 - 20 FRONT SUSPENSION AND AXLE ZJ
INSTALLATION (2) Locate a socket that is larger in diameter than
(1) Thoroughly clean the axle shaft and apply a the bearing cap. Place the socket (receiver) against
thin film of Mopar Wheel Bearing Grease to the shaft the yoke and around the perimeter of the bearing cap
splines, seal contact surface, hub bore. to be removed. Locate a socket that is smaller in di-
(2) On 4WD vehicles, install the axle shaft into the ameter than the bearing cap. Place the socket (driv-
housing and differential side gears. Avoid damaging er) against the opposite bearing cap. Position the
the axle shaft oil seals in the differential. yoke with the sockets in a vise (Fig. 9).
(3) Install the hub bearing and brake dust shield
to the knuckle.
(4) Install the hub to knuckle bolts and tighten to
102 N⅐m (75 ft. lbs.) torque.
(5) Install the hub washer and nut. Tighten the
hub nut to 237 N⅐m (175 ft. lbs.) torque. Install the
nut retainer and a new cotter pin (Fig. 7).
(6) Install the brake components, refer to Group 5,
Brakes.
(7) Install the wheel and tire assembly.
(8) Lower the vehicle.
AXLE SHAFT— CARDAN U-JOINT
DISASSEMBLY
Single cardan U-joints are not serviceable. If defec-
tive, they must be replaced as a unit. If the bearings,
seals, spider or bearing caps are damaged or worn,
replace the complete U-joint.
CAUTION: Clamp only the forged portion of the
yoke in the vise. Also, to avoid distorting the yoke, Fig. 9 Yoke Bearing Cap Removal
do not over tighten the vise jaws. (3) Compress the vise jaws to force the bearing cap
into the larger socket (receiver).
(1) Remove the bearing cap retaining snap rings
(4) Release the vise jaws. Remove the sockets and
(Fig. 8).
bearing cap that was partially forced out of the yoke.
(5) Repeat the above procedure for the remaining
bearing cap.
(6) Remove the remaining bearing cap, bearings,
seals and spider from the propeller shaft yoke.
CLEANING AND INSPECTION
(1) Clean all the U-joint yoke bores with cleaning
solvent and a wire brush. Ensure that all the rust
and foreign matter are removed from the bores.
(2) Inspect the yokes for distortion, cracks and
worn bearing cap bores.
(3) Replace the complete U-joint if any of the com-
ponents are defective.
ASSEMBLY
(1) Pack the bearing caps 1/3 full of wheel bearing
lubricant. Apply extreme pressure (EP), lithium-base
lubricant to aid in installation.
(2) Position the spider in the yoke. Insert the seals
and bearings. Tap the bearing caps into the yoke
Fig. 8 Axle Shaft Outer U-Joint bores far enough to hold the spider in position.
(3) Place the socket (driver) against one bearing
It can be helpful to saturate the bearing caps cap. Position the yoke with the socket wrench in a
with penetrating oil prior to removal. vise.
21. ZJ FRONT SUSPENSION AND AXLE 2 - 21
(4) Compress the vise to force the bearing caps into If joint is noisy or worn, bypass following dis-
the yoke. Force the caps enough to install the retain- assembly and replace entire unit and boot.
ing clips.
(5) Install the bearing cap retaining clips. DISASSEMBLY
(6) Install the axle shaft, refer to Hub Bearing and (1) Remove retaining clamps from the outer CV
Axle Shaft installation. joint and discard. Slide the boot off the outer joint
and down the shaft.
AXLE SHAFT— CV-JOINT (2) Remove the lubricant to expose the joint com-
ponents (Fig. 10).
HANDLING AND CLEANING PRECAUTIONS (3) Clamp the shaft in a vise (with soft jaws). Give
Extreme care must be exercised to avoid punctur- a sharp tap to the top of the housing to dislodge joint
ing or tearing the boots. Also avoid damage to the from internal circlip. Slide the joint from the shaft.
ABS tone ring pressed onto the CV-joint. (Fig. 11).
The rubber material in shaft boots is not com-
patible with oil, gasoline, or petroleum based
cleaning solvents. Do not expose the rubber
boots to any of these fluids. Use only soap and
water to clean the rubber boots. After cleaning,
the rubber boot must be thoroughly rinsed and
dried.
INSPECTION
The most common failure of CV-joints is torn or
ripped boots and subsequent lubricant loss or con-
tamination. Look for lubricant around the exterior of
boot. Check for a punctured or torn boot or retaining
clamp loose. If joint was operating satisfactorily and
grease does not appear contaminated, replace boot.
When a CV drive shaft is removed from the vehicle
for service, the boot should be properly cleaned. In- Fig. 11 Joint Removal
spect the boot for cracks, tears and scuffed areas on (4) Remove the surplus lubricant. Apply installa-
the surfaces. If any of these conditions exist boot re- tion alignment marks on the bearing hub, bearing
placement is recommended. cage and housing with dabs of paint (Fig. 12).
Fig. 10 CV Joint Components
22. 2 - 22 FRONT SUSPENSION AND AXLE ZJ
Fig. 12 Ball Access Fig. 14 Bearing Cage & Hub Removal
(5) Place the stub shaft in a soft-jawed vise to
avoid damage to the shaft splines.
(6) Press down on one side of the bearing cage/hub
to tilt the cage. This will provide access to a ball at
the opposite side of the cage. If the CV joint is tight,
use a hammer and brass drift to loosen the bearing
hub. Do not hit the bearing cage with the drift.
(7) Remove the ball from the bearing cage (Fig.
13). If necessary, a small pry bar can be used to pry
the ball loose from the cage.
Fig. 15 Bearing Hub Removal
(1) Inspect the lubricant for grit, dirt, water dam-
age and metallic particles.
(2) Clean all the components with an appropriate
solvent and dry them with compressed air.
(3) Inspect the ball raceways in the housing for ex-
cessive wear or scoring.
(4) Examine the stub shaft splines and threads for
damage.
(5) Inspect the balls for pitting, cracks, scoring and
Fig. 13 Ball Removal excessive wear. A dull exterior surface is normal.
(6) Inspect the bearing cage for wear, grooves, rip-
(8) Repeat the step above until all six balls are re-
ples, cracks and chipping.
moved from the bearing cage.
(7) Inspect the bearing hub for excessive wear and
(9) Tilt the bearing cage and hub to a vertical po-
scoring on ball raceways.
sition to remove (Fig. 14).
(10) Insert one of the bearing hub lands into the ASSEMBLY
adjacent cage window and roll it out of the cage (Fig. (1) Lightly apply lubricating oil to all joint compo-
15). nents before assembling them.
(2) Align the bearing hub, cage and housing ac-
INSPECTION
cording to the alignment reference marks.
Polished contact surface areas on raceways
and bearing cage spheres are normal. If joint
was noisy or vibrated it should be replaced.
23. ZJ FRONT SUSPENSION AND AXLE 2 - 23
(3) Insert one of the bearing hub lands into a bear-
ing cage window and roll it into the cage (Fig. 16).
Rotate the bearing hub 90° to complete the installa-
tion (Fig. 17).
Fig. 18 Bearing Cage & Hub Installation
Fig. 16 Bearing Hub Installation
Fig. 19 Assembly Installed
Fig. 17 Assembled Bearing Cage & Hub
(4) Insert bearing cage/hub into the housing (Fig.
18). Rotate the cage/hub 90° to complete the installa-
tion. Ensure the tapered edge is facing outward
(Fig. 19).
(5) Apply the lubricant included with the replace-
ment rubber boot to the ball raceways. Spread the lu-
bricant equally between all the raceways. One packet
of lubricant is sufficient to lubricate the joint.
(6) Tilt the bearing hub and cage and install the
balls in the raceways (Fig. 20). Fig. 20 Ball Installation In Raceway
(7) Install the rubber boot on the axle shaft. En-
sure the clamp sealing area is in the grooved section
of the axle shaft. Install a new clamp.
24. 2 - 24 FRONT SUSPENSION AND AXLE ZJ
(8) Engage the splines and install the joint onto
the shaft. Tap sharply with mallet until seated (Fig.
21).
Fig. 21 Joint Installation
(9) Ensure that the snap ring is properly seated in
the housing. Pull the outer CV joint from the shaft to Fig. 22 Steering Knuckle Removal/Installation
test, it should not come off.
LOWER BALL STUD REPLACEMENT
(10) Install remaining amount of lubricant to cage
(1) Position tools as shown to remove and install
and balls.
ball stud (Fig. 24).
(11) Place the large diameter end of the rubber
boot over the edge of the housing. Ensure that the KNUCKLE INSTALLATION
boot is not twisted. (1) Position the steering knuckle on the ball studs.
(12) Ensure the clamp sealing area is in the (2) Install and tighten the bottom retaining nut to
grooved section of the housing. Install a new clamp. 108 N⅐m (80 ft. lbs.) torque. Install new cotter pins.
(13) Install the axle shaft, refer to Hub Bearing (3) Install and tighten the top retaining nut to 101
and Axle Shaft installation. N⅐m (75 ft. lbs.) torque. Install new cotter pin.
(4) Install the Hub Bearing and Axle Shaft. Refer
STEERING KNUCKLE AND BALL STUDS to the installation procedure.
Ball Stud service procedures below require removal (5) Install tie-rod or drag link end onto the steer-
of the hub bearing and axle shaft. Removal and in- ing knuckle arm. Install the ABS sensor wire and
stallation of upper and lower ball stud requires use bracket to the knuckle, refer to Group 5, Brakes for
of Tool Kit 6289 (J34503-A). proper set-up.
KNUCKLE REMOVAL
(1) Remove hub bearing and axle shaft. Refer to
the Removal procedures in this Group.
(2) Remove tie-rod or drag link end from the steer-
ing knuckle arm. Remove the ABS sensor wire and
bracket from knuckle.
(3) Remove the cotter pin from the upper ball stud
nut. Remove the upper and lower ball stud nuts.
(4) Strike the steering knuckle with a brass ham-
mer to loosen. Remove knuckle from axle tube yokes
(Fig. 22).
UPPER BALL STUD REPLACEMENT
(1) Position tools as shown to remove and install
ball stud (Fig. 23).
26. 2 - 26 FRONT SUSPENSION AND AXLE ZJ
AXLE BUSHING REPLACEMENT CAUTION: Do not spread over 0.38 mm (0.015 in.). If
Refer to Axle Bushing Replacement in the Front the housing is spread too much, it could be dis-
Suspension section. torted or damaged.
DIFFERENTIAL REMOVAL (5) Separate the housing a maximum of 0.38 mm
To service the differential the axle shafts must be (0.015 in.). Measure the distance with the dial indi-
removed. Refer to the removal procedures in this cator (Fig. 26).
Group. (6) Remove the dial indicator.
(1) Note the installation reference letters (7) Pry the differential case loose from the housing.
stamped on the bearing caps and housing ma- To prevent damage, pivot on housing with the end of
chined sealing surface (Fig. 25). the pry bar against spreader (Fig. 27).
Fig. 25 Bearing Cap Identification
(2) Remove the differential bearing caps.
(3) Position Spreader W-129B with the tool dowel
pins seated in the locating holes (Fig. 26). Install the
holddown clamps and tighten the tool turnbuckle fin-
ger-tight. Fig. 27 Differential Removal
(8) Remove the case from housing. Mark or tag
bearing cups indicating which side they were re-
moved. Remove spreader from housing.
AXLE SHAFT OIL SEALS
(1) Remove the inner axle shaft seals with a pry
bay.
(2) Install oil seals with Discs 6798 and Turn-
buckle 6797 (Fig. 28). Tighten tool until disc bottoms
in housing.
DIFFERENTIAL DISASSEMBLY
(1) Remove the bearings from the differential case
with Press C-293PA, Plug C-293-3, Adapter C-293-39
(Fig. 29).
Fig. 26 Spread Differential Housing Place adapter rings so they do not damage
the bearing cage.
(4) Install a pilot stud at the left side of the differ- (2) Remove bearing shims from case hubs and
ential housing. Attach Dial Indicator to housing pilot mark them (with hub identity) for assembly refer-
stud. Load the indicator plunger against the opposite ence. Record the thickness of the shims.
side of the housing (Fig. 26) and zero the indicator. (3) Clamp the differential case in a vise equipped
with soft jaws. Remove and discard the ring gear
27. ZJ FRONT SUSPENSION AND AXLE 2 - 27
Fig. 30 Ring Gear Removal
Fig. 28 Axle Shaft Oil Seal Installation
Fig. 31 Mate Shaft Lock Pin Removal
Fig. 29 Differential Bearing Removal
bolts. Tap the ring gear with a rawhide or plastic
mallet and remove (Fig. 30).
(4) Use a drift to remove the pinion gear mate
shaft lock pin (Fig. 31).
28. 2 - 28 FRONT SUSPENSION AND AXLE ZJ
(5) Remove the mate shaft with a drift and ham-
mer (Fig. 32).
Fig. 34 Pinion Yoke Removal
damaged. This will damage the front bearing
Fig. 32 Mate Shaft Removal rollers and bearing cup. The front bearing and
(6) Rotate the differential side gears and remove cup must be replaced.
the pinion mate gears and thrust washers (Fig. 33). (3) Remove the pinion gear seal with a slide ham-
mer or pry out with bar.
Fig. 33 Pinion Mate Gear Removal Fig. 35 Remove Pinion Gear
(7) Remove the differential side gears and thrust (4) Remove oil slinger, front bearing.
washers. (5) Remove the front pinion bearing cup and seal
(8) Remove the case from the vise. with Remover D-147 and Handle C-4171 (Fig. 36).
(6) Remove the rear bearing cup from housing with
PINION REMOVAL/DISASSEMBLY Remover D-149 and Handle C-4171 (Fig. 37).
(1) Remove the pinion yoke nut and washer. Use
(7) Remove the collapsible preload spacer (Fig. 38).
Remover C-452 and Wrench C-3281 to remove the
(8) Remove the inner bearing from the pinion with
pinion yoke (Fig. 34).
Puller C-293PA and Adapter C-293-39 (Fig. 39).
(2) Drive out pinion gear from housing with raw-
Place adapter rings so they do not damage
hide or plastic hammer (Fig. 35). Catch the pinion
the bearing cage.
with your hand to prevent it from falling and being
29. ZJ FRONT SUSPENSION AND AXLE 2 - 29
Fig. 36 Front Bearing Cup Removal Fig. 38 Collapsible Spacer
Fig. 37 Rear Bearing Cup Removal
(9) Remove the oil slinger (select thickness-produc- Fig. 39 Inner Bearing Removal
tion) from the pinion gear shaft. Record the thick- Clean the axle shaft tubes with a stiff wire brush
ness of slinger. or clean cloth.
Inspect the components for;
CLEANING/INSPECTION • Smooth appearance with no broken/dented sur-
Wash differential components with cleaning solvent
faces on the bearing rollers or the roller contact sur-
and dry with compressed air. Do not steam clean
faces
the differential components.
• Bearing cups must not be distorted or cracked
Wash bearings with solvent and towel dry, do spin
• Machined surfaces should be smooth and without
dry bearings with compressed air. Cup and bearing
any raised edges
must be replaced as matched sets only.
30. 2 - 30 FRONT SUSPENSION AND AXLE ZJ
• Raised metal on shoulders of cup bores should be
removed with a hand stone
• Wear and damage to pinion gear mate shaft, pin-
ion gears, side gears and thrust washers. Replace as
a matched set only.
• Ring and pinion gear for worn and chipped teeth
• Ring gear for damaged bolt threads. Replaced as a
matched set only.
• Pinion yoke for cracks, worn splines, pitted areas,
and a rough/corroded seal contact surface. Repair or
replace as necessary.
• Preload shims for damage and distortion. Install
new shims if necessary.
DIFFERENTIAL ASSEMBLY
(1) Install the following components in the differ-
ential case.
• Differential side gears and thrust washers
• Pinion gears and thrust washers
• Pinion gear mate shaft (align holes in shaft and
case)
(2) Install and seat the locking roll pin in the dif-
ferential case and mate shaft with a punch and ham- Fig. 41 Ring Gear Bolt Installation
mer (Fig. 40). Peen metal part of case over pin in two (5) Lubricate all differential components with a
places a 180 degrees apart. light coat of grease or hypoid gear lubricant.
If replacement gears and thrust washers were
installed, it is not necessary to measure the PINION GEAR DEPTH INFORMATION
gear backlash. Correct fit is due to close ma- Ring and pinion gears are supplied as matched sets
chining tolerances during manufacture. only. The identifying numbers for the ring and pinion
gear are etched into the face of each gear (Fig. 42). A
plus (+) number, minus (-) number or zero (0) is
etched into the face of the pinion gear. This number
is the amount (in thousandths of an inch) the depth
varies from the standard depth setting of a pinion
etched with a (0). The standard setting from the cen-
terline of the ring gear to the back face of the pinion
is 92.1 mm (3.625 inches) for Model 30 axles (Fig.
43). The standard depth provides the best teeth con-
tact pattern.
Fig. 40 Mate Shaft Pin Installation
(3) Invert the differential case and start two ring
gear bolts. This will provide case-to-ring gear bolt
hole alignment.
(4) Install new ring gear bolts and alternately
Fig. 42 Pinion Gear ID Numbers
tighten to 95-122 N⅐m (70-90 ft. lbs.) torque (Fig. 41).
31. ZJ FRONT SUSPENSION AND AXLE 2 - 31
THE BUTTON END ON THE PINION GEAR HEAD
IS NO LONGER A MACHINED-TO-SPECIFICATIONS
SURFACE. DO NOT USE THIS SURFACE FOR PIN-
ION DEPTH SET-UP OR CHECKING (Fig. 43).
Fig. 43 Pinion Gear Head Fig. 44 Shim and Slinger Location
Compensation for depth variance is achieved by a se-
to compensate for the difference in depth vari-
lected thickness oil slinger (production) or shims (ser-
ances. Refer to the Depth Variance charts.
vice). The slinger is placed between the inner pinion
Note where Old and New Pinion Marking columns
bearing cone and gear head (Fig. 44). The shim pack is
placed under the inner (rear) bearing cup. To change intersect. Intersecting figure represents plus or mi-
the pinion adjustment, shims are available in thick- nus amount needed.
nesses of 0.003, 0.005, and 0.010 inch. If equipped, the For example, if old pinion is plus (+) 1 and the new
oil slinger or baffle must be measured and the pinion is minus (-) 3, intersecting figure is (+) 0.004
thickness included with the total shim pack. inch (0.10 mm). Add this amount to the original
If a new gear set is being installed, note the shim. Or if the old pinion is (-) 3 and the new pinion
number etched into both pinion gears. Add or is (-) 2, intersecting figure is (-) 0.001 inch (0.025
subtract the thickness of original depth shims
PINION GEAR DEPTH VARIANCE
32. 2 - 32 FRONT SUSPENSION AND AXLE ZJ
mm). Subtract this amount from original shim. Refer
to the Pinion Gear Depth Variance Chart.
DIFFERENTIAL AND PINION MEASUREMENT
DIFFERENTIAL ZERO END PLAY
MEASUREMENT
(1) Place Master Differential Bearing D-134
(D-348) on the case hubs (Fig. 45).
Fig. 46 Differential Case End Play Measurement
PINION GEAR DEPTH MEASUREMENT
Pinion gear depth measurement is necessary
when;
• Axle housing or differential case is replaced
• Pinion select shim pack is unknown
• Ring and pinion gears are replaced
Measurements are done with pinion cups and pin-
ion bearings installed in housing. Take measure-
Fig. 45 Master Bearing Tools On Hubs ments with Pinion Gauge Set 6774, Pinion Block
6733 and Dial Indicator C-3339 (Fig. 47).
(2) Install a pilot stud at the right side of housing.
Attach Dial Indicator to the pilot stud. Load indica-
tor plunger against the back of the ring gear (Fig.
46).
(3) Insert a small pry bar between the bearing cap
and left side of differential case. Pry the case as far
as possible to right side (Fig. 46). Zero the dial indi-
cator pointer.
(4) Pry the case to left side and record the travel
distance.
The measurement above is the shim thickness
necessary for case zero end-play. The total
thickness will be determined during the ring
gear backlash adjustment.
(5) Remove indicator and pilot stud.
Fig. 47 Pinion Gear Depth Gauge Tools
33. ZJ FRONT SUSPENSION AND AXLE 2 - 33
(1) Assemble Pinion Gauge Set, Pinion Block and
pinion bearings. Install assembly into differential
pinion gear bore and hand tighten cone (Fig. 48).
Fig. 50 Pinion Gear Depth Measurement
tal shim pack thickness. Include oil slinger or baf-
fle thickness with the total shim pack
Fig. 48 Pinion Height Block thickness.
(6) Remove the measurement tools from the differ-
(2) Place Arbor Disc 6732 on Arbor D-115-3 and po-
ential housing.
sition in the bearing cradles (Fig. 49). Install differ-
ential bearing caps on Arbor Discs and tighten caps
PINION GEAR ASSEMBLY/INSTALLATION
snug only.
(1) Place the needed shim pack thickness in the
Arbor Discs have different steps to fit other
pinion gear rear bearing bore (service only). Install
axle sizes. Pick correct size step for axle being
serviced. the bearing cup with Installer D-146 and Driver
Handle C-4171 (Fig. 51). Ensure cup is correctly
seated.
Fig. 49 Gauge Tools In Housing
(3) Firmly place Scooter Block and Dial Indicator
on pinion height block tool and zero the dial indicator
pointer.
(4) Slide the Scooter Block across the arbor while
observing indicator (Fig. 50). Record the longest
travel distance, whether inward (-) or outward (+),
indicated by the pointer. Fig. 51 Pinion Rear Bearing Cup Installation
The plunger travel indicated, plus or minus
the variance etched in the gear is the required (2) Install the pinion front bearing cup with In-
thickness for the depth shims. staller D-144 and Handle C-4171 (Fig. 52).
(5) Measure the thickness of each depth shim with
a micrometer. Then combine the shims needed for to-
34. 2 - 34 FRONT SUSPENSION AND AXLE ZJ
(4) Install a new collapsible preload spacer on pin-
ion shaft. (Fig. 54).
Fig. 52 Pinion Front Bearing Cup Installation
(3) If used, place the oil slinger on the pinion gear.
Install the rear (inner) bearing on the pinion gear
with Installer W-262 (Fig. 53).
Fig. 54 Collapsible Preload Spacer
(5) Install pinion front bearing and oil slinger. Ap-
ply a light coating of gear lubricant on the lip of pin-
ion seal. Install seal with Installer D-163 and Handle
C-4171 (Fig. 55).
Fig. 53 Rear Bearing Installation
Fig. 55 Pinion Seal Installation
35. ZJ FRONT SUSPENSION AND AXLE 2 - 35
(6) Install pinion gear into differential housing.
(7) Install yoke with Installer W-162D and Wrench
C-3281 (Fig. 56).
Fig. 57 Tightening Pinion Nut
Fig. 56 Pinion Yoke Installation
(8) Install the yoke washer AND A NEW NUT on
the pinion gear. Tighten the nut to 216 N⅐m (160
ft. lbs.).
CAUTION: Never loosen the pinion gear nut to de-
crease the pinion gear bearing preload torque. If the
specified preload torque exceeds 352 N⅐m (260 ft.
lbs.) a new collapsible spacer must be installed.
The torque sequence will have to be repeated.
(9) Use Flange Wrench C-3281 to retain the yoke
(Fig. 57). Slowly tighten the nut in small increments
until the rotating torque is achieved. Measure the
preload torque frequently to avoid over-tight-
ening the nut.
(10) Check bearing preload torque with an inch
pound torque wrench (Fig. 58). The torque necessary
to rotate the pinion gear should be;
• Original Bearings: 1 to 3 N⅐m (10 to 20 in. lbs.). Fig. 58 Check Pinion Gear Torque
• New Bearings: 1.5 to 4 N⅐m (15 to 35 in. lbs.). Ensure ring and pinion gear teeth are tightly
meshed. Zero the indicator.
DIFFERENTIAL SHIM PACK MEASUREMENT AND (4) Insert a small pry bar between the bearing cap
ADJUSTMENT and left side of differential case. Pry the case as far
(1) Place Master Differential Bearing D-134 as possible to right side (Fig. 60). Zero the dial indi-
(D-348) on the case hubs. cator pointer.
(2) Place Differential assembly in the housing. As- (5) Repeat the measurement several times to check
semble Differential bearing caps. consistency. Record the travel distance.
(3) Install a pilot stud at the left side of housing. The measurement above shows shim thick-
Attach Dial Indicator to housing. Load the indicator ness necessary to eliminate ring gear backlash.
plunger against the back of the ring gear (Fig. 59). Subtract this thickness from case zero end-play
36. 2 - 36 FRONT SUSPENSION AND AXLE ZJ
ing on the hub with Bearing Installer C-3716A and
Driver Handle C-4171 (Fig. 61).
Fig. 59 Shim Pack Measurement
shim thickness (Fig. 60). The shims must be
Fig. 61 Differential Bearing Installation
placed at the ring gear side between the case
and bearing. (10) Position the remaining zero end-play shims on
hub at opposite side of case. Include an additional
0.015 in. (0.38 mm) thick shim on this hub. This will
provide the required differential bearing preload.
(11) Install bearings on hubs with Installer
C-3716A and Handle C-4171 (Fig. 61).
(12) Match each bearing cup with bearing (origi-
nal). Install the cups on the bearings.
DIFFERENTIAL INSTALLATION
(1) Position Spreader W-129B with the tool dowel
pins seated in the locating holes (Fig. 62). Install the
holddown clamps and tighten the tool turnbuckle fin-
ger-tight.
Fig. 60 Shim Pack Calculations
(6) Remove indicator and pilot stud.
(7) Remove the differential case from housing.
(8) Remove the master bearing tools from the dif-
ferential case hubs.
(9) Position the backlash shims (with determined
thickness) on case hub (ring gear side). Install bear-
Fig. 62 Spread Differential Housing
37. ZJ FRONT SUSPENSION AND AXLE 2 - 37
(2) Install a pilot stud at the left side of the differ- If backlash must be adjusted, transfer shims from
ential housing. Attach Dial Indicator to housing pilot one side of carrier to the other side. Adjust the back-
stud. Load the indicator plunger against the opposite lash accordingly (Fig. 64). DO NOT INCREASE
side of the housing (Fig. 63) and zero the indicator. THE TOTAL SHIM PACK THICKNESS, EXCES-
SIVE BEARING PRELOAD AND DAMAGE MAY
CAUTION: Do not spread over 0.38 mm (0.015 in). If OCCUR.
the housing is over-separated, it could be distorted
or damaged.
(3) Separate the housing enough to install the case
in the housing. Measure the distance with the dial
indicator (Fig. 62).
(4) Remove the dial indicator.
(5) Install case in the housing. Tap the differential
case to ensure the bearings are fully seated. Remove
the spreader.
(6) Install the bearing caps at their original loca-
tions. Tighten the bearing cap bolts to 61 N⅐m (45 ft.
lbs.) torque.
BACKLASH AND CONTACT PATTERN ANALYSIS
(1) Rotate assembly several revolutions to seat
bearings. Measure backlash at three equally spaced
locations around the perimeter of the ring gear with
a dial indicator (Fig. 63).
Fig. 64 Backlash Shim Adjustment
If the mesh and backlash steps have been followed
in the procedures above, good gear teeth contact pat-
terns should exist.
The ring gear teeth contact patterns will show if
the pinion gear depth shim(s) have the correct thick-
ness. It will also show if the ring gear backlash has
been adjusted correctly. The backlash must be main-
tained within the specified limits until the correct
tooth contact patterns are obtained.
(2) Apply a thin coat of hydrated ferric oxide to
the drive and coast side of the ring gear.
(3) Rotate the ring gear several revolutions in both
directions while a load is being applied. Insert a pry
bar between the differential housing and the case
Fig. 63 Ring Gear Backlash Measurement flange. This action will produce distinct contact pat-
The ring gear backlash must be within 0.005 - terns on both the drive side and coast side of the ring
0.008 inch (0.12 - 0.20 mm). It cannot vary more gear teeth.
than 0.002 inch (0.05 mm) between the points (4) Note patterns in compound. Refer to (Fig. 65)
checked. for interpretation of contact patterns and adjust ac-
cordingly.
38. 2 - 38 FRONT SUSPENSION AND AXLE ZJ
Fig. 65 Gear Tooth Contact Patterns
39. ZJ FRONT SUSPENSION AND AXLE 2 - 39
FINAL ASSEMBLY
(1) Install the axle shafts. Refer to Axle Shaft In-
stallation in this Group.
(2) Scrape the residual sealant from the housing
and cover mating surfaces. Clean the mating surfaces
with mineral spirits. Apply a bead of MOPAR Sili-
cone Rubber Sealant on the housing cover (Fig. 66).
Allow the sealant to cure for a few minutes.
Install the housing cover within 5 minutes af-
ter applying the sealant. If not installed the
sealant must be removed and another bead ap-
plied.
(3) Install the cover on the differential with the at-
taching bolts. Install the identification tag. Tighten
the cover bolts with 41 N⅐m (30 ft. lbs.) torque.
CAUTION: Overfilling the differential can result in
lubricant foaming and overheating.
(4) Refill the differential housing with the specified
quantity of MOPAR Hypoid Gear Lubricant.
(5) Install the fill hole plug and tighten to 34 N⅐m
Fig. 66 Typical Housing Cover With Sealant
(25 ft. lbs.) torque.
AXLE SPECIFICATIONS
MODEL 30 AXLE Ring Gear
Axle Type ........................................................Hypoid Diameter .....................................18.09 cm (7.125 in.)
Lubricant................SAE Thermally Stable 80W-90 Backlash....................0.12-0.20 mm (0.005-0.008 in.)
Lube Capacity ................................1.18 L (2.5 pts.) Pinion Std. Depth ...................92.1 mm (3.625 in.)
Axle Ratio....................................................3.55 3.73 Pinion Bearing Preload Torque
Differential Original Bearing ..................1-2 N⅐m (10-20 in. lbs.)
Bearing Preload..........................0.38 mm (0.015 in.) New Bearing......................1.5-4 N⅐m (15-35 in. lbs.)
TORQUE SPECIFICATIONS
FRONT SUSPENSION COMPONENTS Bolts............................................121 N⅐m (90 ft. lbs.)
Nut..............................................121 N⅐m (90 ft. lbs.)
DESCRIPTION ................................................TORQUE Support Bolts...............................95 N⅐m (70 ft. lbs.)
Shock Absorber
Upper Nut....................................23 N⅐m (17 ft. lbs.) MODEL 30 AXLE
Lower Nut .................................28 N⅐m (250 in. lbs.)
Suspension Arm Upper DESCRIPTION ................................................TORQUE
Nuts ..............................................75 N⅐m (55 ft. lbs.) Fill Hole Plug ...........................34 N⅐m (25 ft. lbs.)
Suspension Arm Lower Diff. Cover Bolt ........................41 N⅐m (30 ft. lbs.)
Nuts ............................................115 N⅐m (85 ft. lbs.) Bearing Cap Bolt .....................61 N⅐m (45 ft. lbs.)
Stabilizer Bar Ring Gear Bolt .............95-122 N⅐m (70-90 ft. lbs.)
Clamp Bolt...................................54 N⅐m (40 ft. lbs.) Axle Nut .................................237 N⅐m (175 ft. lbs.)
Link Upper Nut ..........................36 N⅐m (27 ft. lbs.) Wheel Brg. Bolt ......................102 N⅐m (75 ft. lbs.)
Link Lower Bolt ..........................95 N⅐m (70 ft. lbs.) Lower Ball Stud .....................108 N⅐m (80 ft. lbs.)
Track Bar Upper Ball Stud .....................101 N⅐m (75 ft. lbs.)
Ball Stud Nut ..............................81 N⅐m (60 ft. lbs.) ABS Sensor Bolt ......................11 N⅐m (96 in. lbs.)
Axle Bracket Bolt........................75 N⅐m (55 ft. lbs.)
Track Bar Bracket