1995 JEEP YJ service

the opposite wheel. Wheels are attached to a hub/
bearings which bolts to the knuckles. The hub/bear-
ing is not serviceable and is replaced as a unit.
Steering knuckles pivot on replaceable ball studs at-
tached to the axle tube yokes.
The upper and lower suspension arms are different
lengths, with bushings at both ends. They bolt the
axle assembly to the body. The lower arms uses
shims at the body mount to allow for adjustment of
caster and drive shaft pinion angle. The suspension
arm travel is limited through the use of jounce
bumpers in compression and shocks absorbers in re-
bound.
Suspension components which use rubber bushings
should be tightened at vehicle ride height. This will
prevent premature failure of the bushing and main-
tain ride comfort. Bushings must never be lubricated.
The coil springs control ride quality and maintain
proper ride height. The coil springs mount up in the
fender shield which is part of the unitized body
bracket. A rubber isolator is located between the top
of the spring and the frame. The bottom of the spring
seats on a axle pad and is retained with a clip.
The shock absorbers dampen jounce and rebound of
the vehicle over various road conditions. The top of
the shock absorbers are bolted to the body. The bot-
tom of the shocks are bolted to the axle spring
bracket.
The stabilizer bar is used to minimize 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 body rails. Links are
connected from the bar to the axle brackets. Stabi-
lizer bar mounts are isolated by rubber bushings.
The track bar is used to minimize front axle side-
to-side movement. The bar is attached to a frame rail
bracket with a ball stud and isolated with a bushing
at the axle bracket.
TUBE AXLE (2WD VEHICLES)
The front axle used on two-wheel drive vehicles is
a one-piece, tubular axle (Fig. 2). The tubular axle
mounts in the same bracketry as the four-wheel
drive axle.
The steering knuckles and hub bearing assemblies
are the same as used on the Model 30 drive axle.
YJ VEHICLES
The Wrangler (YJ) front suspension is leaf spring
design comprised of (Fig. 3);
²Drive axle
²Track bar
²Stabilizer bar
²Leaf springs
²Dual-action shock absorbers
²Jounce bumpers (used to limit the travel of the
suspension)The front suspension has semi-elliptic multi-leaf
springs mounted to the axle assembly. The rearward
end of the springs are mounted to the frame rail
hangers. The forward end of the springs are attached
to the frame with shackles. The springs and shackles
use rubber bushings to isolate road noise. The shack-
les allow the springs to change their length as the
vehicle moves over various road conditions. The
Fig. 2 Front AxleÐ2WD Vehicles
Fig. 3 YJ Front Suspension
2 - 2 FRONT SUSPENSION AND AXLEJ

spring and axle travel (jounce or rebound) is limited
through use of rubber bumpers mounted on the
frame.
Suspension components which use rubber bushings
should be tightened at vehicle ride height. This will
prevent premature failure of the bushing and main-
tain ride comfort. The bushings should never be lu-
bricated.
The shocks absorbers dampen jounce and rebound
of the vehicle over various road conditions. The top of
the shock absorbers bolt to the frame. The bottom of
the shocks bolt to the axle brackets.
The stabilizer bar is used to minimize vehicle front
sway during turns. The spring steel bar helps control
vehicle body in relationship to the suspension move-
ment. The bar extends across the front underside of
the chassis and connects to the frame rails. Links
connect the bar to the axle brackets. Stabilizer bar
mounts are isolated by rubber bushings.
The track bar is used to minimize front axle side-
to-side movement. The track bar is attached to a
frame rail bracket and axle bracket. The bar uses
bushings at both ends.
FRONT DRIVE AXLE
It is not necessary to remove the complete axle
from the vehicle for routine differential service. If the
differential housing or axle shaft tubes are damaged,
the complete axle assembly can be removed and ser-
viced.
For complete drive axle assembly removal and in-
stallation refer to Drive Axle Assembly Replacement
in this Group.
The removable cover provides for servicing without
removing axle from vehicle.
The integral type housing, hypoid gear design has
the centerline of the pinion set above the centerline
of the ring gear.
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. 4). Build date identification
codes are stamped on the axle shaft tube cover side.
XJ and YJ axles are equipped with an optional
A.B.S. brake system. 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.
²XJ vehicles use a non-disconnect axle.
²YJ vehicles use a vacuum disconnect axle (Fig. 5).
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. Thepinion gear is fitted in a bore in the differential case
and is positioned at a right angle to the axle shafts.
In operation, power flow occurs as follows:
²Pinion gear rotates the ring gear
²Ring gear (bolted to the differential case) rotates
the case
²Differential pinion gears (mounted on the pinion
mate shaft in the case) rotate the side gears
²Side gears (splined to the axle shafts) rotate the
shafts
During straight-ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to gears is di-
vided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 6).
When turning corners, the outside wheel must
travel a greater distance than the inside wheel. This
difference must be compensated for in order to pre-
vent the wheels from scuffing and skidding through
the turn. To accomplish this, the differential allows
Fig. 4 Model 30 Differential Cover
Fig. 5 Disconnect Feature
JFRONT SUSPENSION AND AXLE 2 - 3

XJ FRONT SUSPENSION
INDEX
page page
Axle Bushing Replacement.................. 12
Coil Spring.............................. 14
Lower Suspension Arm..................... 13
Service Information........................ 11
Shock Absorber.......................... 13Spring and Shock Diagnosis................. 13
Stabilizer Bar............................ 11
Track Bar............................... 11
Upper Suspension Arm..................... 12
SERVICE INFORMATION
Periodic lubrication of the steering system and sus-
pension components is required. Refer to Group 0,
Lubrication And Maintenance for the service inter-
val.
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
(1) Install the track bar at axle tube bracket.
Loosely install the retaining bolt and flag nut (Fig.
1).
(2) It may be necessary to pry the axle assembly
over to install the track bar at the frame rail. Install
track bar at the frame rail bracket. Install the re-
taining nut on the stud (Fig. 1).
(3) Remove the supports and lower the vehicle.
(4) Tighten the retaining bolt at the axle shaft
tube bracket to 100 Nzm (74 ft. lbs.) torque.
(5) Tighten the ball stud nut to 81 Nzm (60 ft. lbs.)
torque. Install a new cotter pin.
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Disconnect the stabilizer bar links from the
axle brackets (Fig. 2).
(3) Disconnect the stabilizer bar from the links.
(4) Disconnect the stabilizer bar clamps from the
frame rails. Remove the stabilizer bar.
INSTALLATION
(1) Inspect stabilizer bar bushings ( Fig. 2). Re-
place bushings if cracked, cut, distorted, or worn.
(2) Position the stabilizer bar on the frame rail and
install the bushings and clamps. Ensure the bar is
centered with equal spacing on both sides. Tighten
the bolts to 75 Nzm (40 ft. lbs.).
(3) 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 Nzm
(70 ft. lbs.) torque.
Fig. 1 Track Bar (LHD)
JFRONT SUSPENSION AND AXLE 2 - 11

YJ FRONT SUSPENSION
INDEX
page page
Leaf Spring.............................. 16
Leaf Spring Eye Bushing Replacement......... 17
Service Information........................ 15
Shock Absorber.......................... 16Spring and Shock Diagnosis................. 15
Stabilizer Bar............................ 15
Track Bar............................... 15
SERVICE INFORMATION
Periodic lubrication of the steering system and sus-
pension components is required. Refer to Group 0,
Lubrication And Maintenance for the service inter-
val.
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 retaining nuts and bolts (Fig. 1)
from the axle bracket and frame bracket. Remove
track bar.
INSTALLATION
(1) Position track bar at axle shaft tube bracket.
Loosely install the retaining bolt and nut (Fig. 1).
(2) Loosely install the retaining bolt and nut at the
frame bracket.
(3) Remove support and lower vehicle.
(4) Tighten the retaining nut at the axle shaft tube
bracket to 100 Nzm (74 ft. lbs.) torque.
(5) Tighten the retaining nut at the frame bracket
to 142 Nzm (105 ft. lbs.) torque.
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the retaining nut from the connecting
link bolt (Fig. 2).
(3) Remove the retaining clamps from frame rails
(4) Remove the stabilizer bar.
INSTALLATION
(1) Inspect the stabilizer bar bushings (Fig. 2). Re-
place the bushings if cracked, cut, distorted, or worn.(2) Position the stabilizer bar on the frame. Install
the retaining brackets and fasteners. Tighten bolts to
41 Nzm (30 ft. lbs.) torque.
(3) Install the link upper bolts and nuts. Tighten
the nuts to 61 Nzm (45 ft. lbs.) torque.
(4) Tighten the link spring bracket nuts to 61 Nzm
(45 ft. lbs.) torque.
(5) Lower the vehicle.
SPRING AND SHOCK DIAGNOSIS
A squeak noise from the shock absorber or springs
can be produced if movement between the rubber
bushings and the metal occurs. This noise can usu-
ally be stopped by tightening the attaching nuts. If
the squeak noise persists, inspect for damaged and
worn bushings, and attaching components. Repair as
necessary if any of these conditions exist.
Fig. 1 Track Bar
JFRONT SUSPENSION AND AXLE 2 - 15

AXLE NOISE/VIBRATION DIAGNOSIS
INDEX
page page
Driveline Snap........................... 19
Gear and Bearing Noise.................... 18
General Information....................... 18Low Speed Knock......................... 19
Vibration................................ 19
GENERAL INFORMATION
Axle bearing problem conditions are usually caused
by:
²Insufficient or incorrect lubricant
²Foreign matter/water contamination
²Incorrect bearing preload torque adjustment
²Incorrect backlash (to tight)
When serviced, the bearings must be cleaned thor-
oughly. They should be dried with lint-free shop tow-
els.Never dry bearings with compressed air.
This will overheat them and brinell the bearing
surfaces. This will result in noisy operation af-
ter repair.
Axle gear problem conditions are usually the result
of:
²Insufficient lubrication
²Incorrect or contaminated lubricant
²Overloading (excessive engine torque) or exceeding
vehicle weight capacity
²Incorrect clearance or backlash adjustment
Insufficient lubrication is usually the result of a
housing cover leak. It can also be from worn axle
shaft or pinion gear seals. Check for cracks or porous
areas in the housing or tubes.
Using the wrong lubricant will cause overheating
and gear failure. Gear tooth cracking and bearing
spalling are indicators of this.
Axle component breakage is most often the result
of:
²Severe overloading
²Insufficient lubricant
²Incorrect lubricant
²Improperly tightened components
Overloading occurs when towing heavier than rec-
ommended loads. Component breakage can occur
when the wheels are spun excessively. Incorrect lu-
bricant quantity contributes to breakage. Loose dif-
ferential components can also cause breakage.
Incorrect bearing preload or gear backlash will not
result in component breakage. Mis-adjustment will
produce enough noise to cause service repair before a
failure occurs. If a mis-adjustment condition is not
corrected, component failure can result.
Excessive bearing preload may not be noisy. This
condition will cause high temperature which can re-
sult in bearing failure.
GEAR AND BEARING NOISE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant. Incorrect backlash, tooth contact, or worn/dam-
aged gears can cause noise.
Gear noise usually happens at a specific speed
range. The range is 30 to 40 mph, or above 50 mph.
The noise can also occur during a specific type of
driving condition. These conditions are acceleration,
deceleration, coast, or constant load.
When road testing, accelerate the vehicle to the
speed range where the noise is the greatest. Shift
out-of-gear and coast through the peak-noise range.
If the noise stops or changes greatly, check for insuf-
ficient lubricant. Incorrect ring gear backlash, or
gear damage can cause noise changes.
Differential side and pinion gears can be checked
by turning the vehicle. They usually do not cause
noise in straight-ahead driving. These gears are
loaded during vehicle turns. If noise does occur dur-
ing vehicle turns, the side or pinion gears could be
worn or damaged. A worn pinion gear mate shaft can
also cause a snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion gear bear-
ings can all produce noise when worn or damaged.
Bearing noise can be either a whining, or a growling
sound.
Pinion gear bearings have a constant-pitch noise.
This noise changes only with vehicle speed. Pinion
bearing noise will be higher because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs the pinion rear bearing is
the source of the noise. If the bearing noise is heard
during a coast, front bearing is the source.
Worn, damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing. The pitch of differential
bearing noise is also constant and varies only with
vehicle speed.
2 - 18 FRONT SUSPENSION AND AXLEJ

SERVICE DIAGNOSIS
2 - 20 FRONT SUSPENSION AND AXLEJ

SERVICE DIAGNOSIS (CONT'D)
JFRONT SUSPENSION AND AXLE 2 - 21

MODEL 30 AXLE AND TUBE AXLE (2WD)
INDEX
page page
Axle Bushing Replacement.................. 34
Axle ShaftÐCardan U-Joint.................. 26
Backlash and Contact Pattern Analysis......... 45
Cleaning/Inspection........................ 37
Differential and Pinion Measurement........... 40
Differential Assembly....................... 38
Differential Disassembly.................... 35
Differential Installation...................... 44
Differential Removal....................... 34
Differential Shim Pack Measurement and
Adjustment............................ 43
Drive Axle Assembly ReplacementÐXJ Vehicles . . 23
Drive Axle Assembly ReplacementÐYJ Vehicles . . 24Final Assembly........................... 46
Hub Bearing and Axle Shaft................. 25
Information.............................. 22
Inner Axle Shaft Oil Seal Replacement......... 35
Lubricant Change......................... 23
Lubricant Specifications..................... 22
Pinion Gear Assembly/Installation............. 42
Pinion Gear Depth Information............... 39
Pinion Removal/Disassembly................. 36
Pinion Seal Replacement................... 25
Steering Knuckle and Ball Studs.............. 32
Vacuum Disconnect AxleÐYJ Vehicles......... 27
INFORMATION
The Model 30 front axles consists of a cast iron dif-
ferential housing with axle shaft tubes extending
from either side. The tubes are pressed into the dif-
ferential housing and welded.
The integral type housing, hypoid gear design has
the centerline of the pinion set above the centerline
of the ring gear.
The axle has a fitting for a vent hose used to re-
lieve internal pressure caused by lubricant vaporiza-
tion and internal expansion.
The axles are equipped with semi-floating axle
shafts, meaning that loads are supported by the hub
bearings. The axle shafts are retained by nuts at the
hub bearings. The hub bearings are bolted to the
steering knuckle at the outboard end of the axle tube
yoke. The hub bearings are serviced as an assembly.
The axles are equipped with ABS brake sensors.
The sensors are attached to the knuckle assemblies
and tone rings are pressed on the axle shaft.Use
care when removing axle shafts as NOT to dam-
age the tone wheel or the sensor.
The stamped steel cover provides a means for in-
spection and servicing the differential.
The Model 30 axle has the assembly part number
and gear ratio listed on a tag. The tag is attached to
the housing cover. Build date identification codes are
stamped on the axle shaft tube cover side.
The differential case is a one-piece design. The dif-
ferential pinion mate shaft is retained with a roll
pin. Differential bearing preload and ring gear back-
lash is adjusted by the use of shims (select thick-
ness). The shims are located between the differential
bearing cones and case. Pinion bearing preload is set
and maintained by the use of collapsible spacer.
COMMAND-TRACÐYJ VEHICLES
The Command-Trac system is a vacuum disconnect
axle. The system has a two-piece axle shaft coupled
together by a shift collar. For two-wheel drive opera-
tion, the vacuum motor and shift fork disengages the
axle shaft splines. For four-wheel drive operation, the
vacuum motor and shift fork engages the axle
splines.
SELEC-TRACÐXJ VEHICLES
The Selec-Trac system is a non-disconnect axle.
Shifting from two-wheel to four-wheel drive is done
at the transfer case.
For XJ vehicles equipped withSelec-Tracand
ABS brake system, refer to Group 5ÐBrakes for ad-
ditional service information.
LUBRICANT SPECIFICATIONS
Multi-purpose, hypoid gear lubricant should be
used for Model 30 axles. The lubricant should have
MIL-L-2105C and API GL 5 quality specifications.
MOPARtHypoid Gear Lubricant conforms to both of
these specifications.
²The factory fill for the Model 30 axle is SAE Ther-
mally Stable 80W-90 gear lubricant.Do not use
heavier weight lubricant, this will cause axle
engagement difficulties.
²The factory installed lubricant quantity for the
NON-DISCONNECT TYPE AXLE is 1.48 L (3.13
pts.).
²The factory installed lubricant quantity for the
VACUUM-DISCONNECT TYPE AXLE is 1.65 L (3.76
pts.).
Refer to Group 0, Lubrication and Maintenance for
additional information regarding temperature range,
viscosity and fluid level.
2 - 22 FRONT SUSPENSION AND AXLEJ