Model 35 Axle JEEP YJ 1995 Service And Repair Manual

FLUID CAPACITIES
Fuel Tank
XJ .....................................................76.4 L (20.2 gal.)
YJ(Standard) ......................................56.8 L (15 gal.)
YJ(Optional) .......................................75.7 L (20 gal.)
Engine Oil
2.5L ......................................................3.8 L (4.0 qts.)
4.0L ......................................................5.7 L (6.0 qts.)
Cooling System
2.5L(XJ).............................................9.5 L* (10 qts.*)
2.5L(YJ) ........................................8.5 L** (9.0 qts.**)
4.0L(XJ) ........................................11.4 L* (12.0 qts.*)
4.0L(YJ) ......................................9.9 L** (10.5 qts.**)
* Includes (2.2 L) (2.3 qts) for coolant recovery res-
ervoir.
** Includes (0.9 L) (1.0 qt.) for coolant recovery res-
ervoir.
Automatic Transmission
Dry fill capacity.*
AW4 (XJ-4.0L) ...................................8.0 L (16.9 pts.)
30RH (YJ-2.5L) .................................8.2 L (17.5 pts.)
32RH (YJ-4.0L) .................................8.2 L (17.5 pts.)
*Depending on type and size of internal cooler,
length and inside diameter of cooler lines, or use ofan auxiliary cooler, these figures may vary. Refer to
Group 21, Transmission for proper fluid fill proce-
dure.
Manual Transmission
AX4/5 (4X2) .........................................3.3 L (3.5 qts.)
AX5 (4X4) ............................................3.2 L (3.3 qts.)
AX15 (4X2) ..........................................3.1 L (3.2 qts.)
AX15 (4X4) ......................................3.15 L (3.32 qts.)
Fill to bottom of fill hole.
Transfer Case
SELEC-TRAC 242(XJ) .......................1.4 L (3.0 pts.)
COMMAND-TRAC 231(XJ) ...............1.0 L (2.2 pts.)
COMMAND-TRAC 231(YJ-Man Trans) ..1.5 L (3.25
pts.)
COMMAND-TRAC 231(YJ-Auto Trans) ....1.0 L (2.2
pts.)
Front Axle
MODEL 30 (YJ) ..............................1.65 L (3.76 pts.)
MODEL 30 (XJ) ..............................1.48 L (3.13 pts.)
Rear Axle
MODEL 35 (XJ-YJ) ........................1.6 L (3.38 pts.*)
8-1/4 (XJ) .........................................2.08 L (4.4 pts.*)
* When equipped with TRAC-LOK, include 2
ounces of Friction Modifier Additive.
JLUBRICATION AND MAINTENANCE 0 - 3

FRONT SUSPENSION AND AXLE
CONTENTS
page page
AXLE NOISE/VIBRATION DIAGNOSIS........ 18
AXLE SPECIFICATIONS................... 49
FRONT WHEEL ALIGNMENT................ 5
GENERAL INFORMATION.................. 1MODEL 30 AXLE AND TUBE AXLE (2WD).... 22
TORQUE SPECIFICATIONS................ 49
XJ FRONT SUSPENSION.................. 11
YJ FRONT SUSPENSION.................. 15
GENERAL INFORMATION
FRONT SUSPENSION
XJ VEHICLES
The XJ front suspension is a link/coil design. This
suspension is use on Left Hand Drive (LHD) and
Right Hand Drive (RHD) vehicles. It is comprised of
(Fig. 1);
²Drive axle (4WD), tube axle (2WD)²Track bar
²Stabilizer bar
²Upper and lower suspension arms
²Coil springs
²Dual-action shock absorbers
²Jounce bumpers
The link/coil suspension allows each wheel to adapt
to different road surfaces without greatly affecting
Fig. 1 XJ Front Suspension (LHD)
JFRONT SUSPENSION AND AXLE 2 - 1

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

(3) Tighten the stabilizer bar to connecting link
nut to 36 Nzm (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.
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 to 75 Nzm (55 ft.
lbs.) torque.
Tighten the nut at the frame bracket to 90 Nzm (66
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.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.
Fig. 2 Stabilizer BarFig. 3 Upper and Lower Suspension Arms
Fig. 4 Axle Bracket Bushing Removal
2 - 12 FRONT SUSPENSION AND AXLEJ

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

(5) Lubricate all differential components with hy-
poid gear lubricant.
PINION GEAR DEPTH INFORMATION
Ring and pinion gears are supplied as matched sets
only. The identifying numbers for the ring and pinion
gear are etched into the face of each gear (Fig. 39). 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.
40). The standard depth provides the best teeth con-
tact pattern.THE BUTTON END ON THE PINION GEAR
HEAD IS NO LONGER A MACHINED-TO-SPECIFI-
CATIONS SURFACE. DO NOT USE THIS SUR-
FACE FOR PINION DEPTH SET-UP OR
CHECKING (Fig. 40).
Compensation for depth variance is achieved by a
selected thickness oil slinger (production) or shims
(service). The slinger is placed between the inner pin-
ion bearing cone and gear head (Fig. 41). The shim
pack is placed under the inner (rear) bearing cup for
service. To change the pinion adjustment, shims are
available in thicknesses of 0.003, 0.005, and 0.010
inch.The oil slinger or baffle must be measured
and the thickness included with the total shim
pack.
Fig. 38 Ring Gear Bolt Installation
Fig. 39 Pinion Gear ID Numbers
Fig. 40 Pinion Gear Head
Fig. 41 Shim Locations
JFRONT SUSPENSION AND AXLE 2 - 39

AXLE SPECIFICATIONS
MODEL 30 FRONT AXLE
Axle Type........................................................Hypoid
Lubricant................SAE Thermally Stable 80W-90
Lube Capacity
YJ .....................................................1.65 L (3.76 pts.)
XJ .....................................................1.48 L (3.13 pts.)
Axle Ratio...................................3.07 3.55 3.73 4.10
DifferentialSide Gear Clearance .0.12-0.20mm (0.005-0.008 in.)
Ring Gear
Diameter .....................................18.09 cm (7.125 in.)
Backlash.........................0-0.15 mm (0.005-0.008 in.)
Pinion Std. Depth...................92.1 mm (3.625 in.)
Pinion Bearing Preload
Original Bearing ..................1-2 Nzm (10-20 in. lbs.)
New Bearing ......................1.5-4 Nzm (15-35 in. lbs.)
TORQUE SPECIFICATIONS
XJ FRONT SUSPENSION COMPONENTS
DESCRIPTION ................................................TORQUE
Shock Absorber
Upper Nut ......................................11 Nzm (8 ft. lbs.)
Lower Nut ....................................23 Nzm (17 ft. lbs.)
Suspension Arm Upper
Front Nut .....................................74 Nzm (55 ft. lbs.)
Rear Nut ......................................89 Nzm (66 ft. lbs.)
Suspension Arm Lower
Front and Rear Nut ..................115 Nzm (85 ft. lbs.)
Stabilizer Bar
Clamp Bolt ...................................54 Nzm (40 ft. lbs.)
Link Upper Nut ..........................36 Nzm (27 ft. lbs.)
Link Lower Nut ..........................95 Nzm (70 ft. lbs.)
Track Bar
Ball Stud Nut ..............................81 Nzm (60 ft. lbs.)
Axle Bracket Bolt ......................100 Nzm (74 ft. lbs.)
Track Bar Bracket
Bolts............................................125 Nzm (92 ft. lbs.)
Nut ..............................................100 Nzm (74 ft. lbs.)
Support Bolts ...............................42 Nzm (31 ft. lbs.)
YJ FRONT SUSPENSION COMPONENTS
DESCRIPTION ................................................TORQUE
Shock Absorber
Upper Nut ......................................13 Nzm (9 ft. lbs.)Lower Nut ....................................61 Nzm (45 ft. lbs.)
Stabilizer Bar
Clamp Bolt ...................................41 Nzm (30 ft. lbs.)
Link Nut ......................................61 Nzm (45 ft. lbs.)
Track Bar
Frame Bracket Nut.................142 Nzm (105 ft. lbs.)
Axle Bracket Nut ......................100 Nzm (74 ft. lbs.)
Spring
U-Bolt Nut .................................122 Nzm (90 ft. lbs.)
Front Shackle Bolt ..................135 Nzm (100 ft. lbs.)
Rear Pivot Bolt........................142 Nzm (105 ft. lbs.)
MODEL 30 AXLE
DESCRIPTION ................................................TORQUE
Fill Hole Plug...........................34 Nzm (25 ft. lbs.)
Diff. Cover Bolt........................41 Nzm (30 ft. lbs.)
Bearing Cap Bolt.....................61 Nzm (45 ft. lbs.)
Ring Gear Bolt.............95-122 Nzm (70-90 ft. lbs.)
Shift Motor Bolt.........................11 Nzm (8 ft. lbs.)
Axle Nut.................................237 Nzm (175 ft. lbs.)
Wheel Brg. Bolt......................102 Nzm (75 ft. lbs.)
Lower Ball Stud.....................108 Nzm (80 ft. lbs.)
Upper Ball Stud.....................101 Nzm (75 ft. lbs.)
ABS Sensor Bolt......................11 Nzm (96 in. lbs.)
JFRONT SUSPENSION AND AXLE 2 - 49

REAR SUSPENSION AND AXLES
CONTENTS
page page
8 1/4 AXLE............................ 30
AXLE NOISE/VIBRATION DIAGNOSIS......... 9
AXLE SPECIFICATIONS................... 51
GENERAL INFORMATION.................. 1
MODEL 35 AXLE........................ 13TORQUE SPECIFICATIONS................ 51
TRAC-LOK DIFFERENTIAL................. 45
XJ SUSPENSION......................... 3
YJ SUSPENSION......................... 6
GENERAL INFORMATION
SUSPENSION COMPONENTS
The Jeep rear suspension is comprised of;
²Drive axle
²Leaf springs
²Dual-action shock absorbers
²Track bar (YJ vehicles)
²Stabilizer bar (XJ vehicles)
²Jounce bumpers
The rear suspension design uses semi-elliptic
multi-leaf springs and a solid drive axle. The forward
end of the springs are mounted to the frame rail
hangers through rubber bushings. The bushings iso-
late road noise as the springs move. The rearward
end of the springs are attached to the frame by the
use of shackles. Again the spring and shackles use
rubber bushings to isolate road noise. The shackles
allow the springs to change their length as the vehi-
cle moves over various road conditions. The spring
and axle travel is limited through the use of bumpers
mounted on frame.
All suspension components that use bushings
should be tightened with the vehicle at normal ride
height. If the springs are not at normal ride position,
vehicle ride comfort could be affected. Rubber bush-
ings must never be lubricated.
The springs are attached to the axle pads with U-
bolts and plates. The springs use a center bolt that
holds the spring leafs in position. The bolt is also
used to locate the spring assembly to the axle pad.
Ride control is accomplished through the use of du-
al-action shock absorbers. The shocks dampen the
jounce and rebound as the vehicle travels over vari-
ous road conditions. The top of shock absorbers are
bolted to the frame bracket. The bottom of the shocks
are bolted to the axle bracket.
The stabilizer bar on the XJ is used to minimize
vehicle rear sway during turns. The bar helps the ve-
hicle maintain a flat attitude to the road surface. The
bar extends across the underside of the chassis and
connects to the frame rails. The links are connectedto the axle brackets. All mounting points of the sta-
bilizer bar are isolated by bushings.
The track bar on the YJ is used to minimize rear
axle side-to-side movement. The track bar is attached
to the frame rail bracket and axle bracket and is iso-
lated with bushings.
The jounce bumpers are used to limit the jounce
and rebound travel of the suspension.
AXLES
The Model 35 axle is standard for XJ and YJ vehi-
cles. The 8 1/4 axle is available in XJ vehicles with-
out ABS brakes.
The Model 35 and 8 1/4 axle housings has a cast
iron center section. Two steel axle shaft tubes are
pressed into the differential housing and welded.
It is not necessary to remove the axle from the ve-
hicle for service. A removable differential cover is
provided for routine vehicle service. If the differential
housing is damaged, the complete axle assembly can
be removed.
For complete drive axle assembly removal and in-
stallation refer to Drive Axle Assembly Replacement
in this Group.
IDENTIFICATION
Model 35 axle has the assembly part number and
gear ratio listed on a tag. The tag is attached to the left
side of the housing cover (Fig. 1). Build date identifica-
tion codes on axles are stamped on the axle shaft tube
cover side. The Model 35 axle has a flat housing cover
gasket flange at the outer edge (Fig. 1).
The 8 1/4 axle has the build date code and gear ra-
tio tags attached to the housing cover (Fig. 2). The
housing cover gasket has a rolled gasket flange at
the outer edge (Fig. 2).
²The Model 35 axle has shaft tubes that are 2.625
inch (66.67 mm) in diameter.
²The 8 1/4 axle has axle shaft tubes that are 3.0-
inch (76.2 mm) in diameter.
JREAR SUSPENSION AND AXLES 3 - 1

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
pinion 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:
²The pinion gear rotates the ring gear²The ring gear (bolted to the differential case) ro-
tates the case
²The differential pinion gears (mounted on the pin-
ion mate shaft in the case) rotate the side gears
²The side 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 the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 3).
When turning corners, the outside wheel must travel
a greater distance than the inside wheel in order to
complete a turn. The difference must be compensated
for, to prevent the tires from scuffing and skidding
through turns. To accomplish this, the differential al-
lows the axle shafts to turn at unequal speeds (Fig. 4).
In this instance, the input torque applied to the pinion
gears is not divided equally. The pinion gears now ro-
tate around the pinion mate shaft in opposite directions.
This allows the side gear and axle shaft attached to the
outside wheel to rotate at a faster speed.
Fig. 4 Differential OperationÐOn Turns
Fig. 1 Model 35 Differential Cover
Fig. 2 8 1/4 Differential Cover
Fig. 3 Differential OperationÐStraight-Ahead Driving
3 - 2 REAR SUSPENSION AND AXLESJ