Page 136 of 2585

STEADY STATE, HIGH SPEED, NO WHEEL SLIP
The roller cage positions the rollers on the input
shaft flats during low and high speed overrunning
and during initial BOC lockup. The roller cage is
rotating at input shaft (propeller shaft) speed at all
times. At low speeds, the friction shoes (Fig. 31) are
pressed against the friction ground via the garter
spring (Fig. 32), creating a drag force on the roller
cage. The drag force positions the cage, which in turn
positions the rollers to one side of the flat. The direc-
tion of this drag force (position of the roller) is depen-
dent on the input (propeller shaft) rotational
direction. Since the rollers are always in contact with
the outer race, due to centrifugal forces, the rollers
want to follow the outer race due to drag. During
overrunning operation, the outer race is rotating
faster than the input; causing the rollers to want to
traverse the flat from one side to the other. During
low speeds, the brake shoes counteract this effect. To
avoid excessive wear, the ground shoes are designed
to lift off from the friction ground due to centrifugal
forces at higher rotational speeds.
To keep the rollers in the overrunning position and
avoid undesired9high speed lockup9, a high speed
latch (Fig. 33) positions the cage before the ground
shoes lift off. A further explanation of the high speed
effects follows as well. Utilizing only the friction
shoes approach means that at high speed the
required ground shoe drag torque would cause exces-
sive brake shoe wear or the roller will begin to
migrate to the opposite side of the flat due to the
drag force of the outer race. This would result in sys-
tem lock-up. (Fig. 34) shows the BOC as it crossesthe speed where the brake shoe force is overcome by
the roller drag on the outer race. Notice that the
roller is locking up on the opposite side of the flat
and the cage supplies no force on the rollers.
Fig. 30 BOC Operation with Front Wheel SlipFig. 31 Front View of BOC
1 - GARTER SPRING
2 - FRICTION BRAKE SHOES
3 - FRICTION GROUND CONNECTED TO GROUND TAB
4 - INPUT SHAFT
Fig. 32 Location of the Grounding Element
1 - DIFFERENTIAL HOUSING
2 - GROUND TAB
3 - GARTER SPRING
RSREAR DRIVELINE MODULE3-37
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
Page 138 of 2585

also shows the outer race/viscous coupler. Notice the
surface (outer race) the rollers mate against when
transferring torque.
DIFFERENTIAL ASSEMBLY
DESCRIPTION
The differential gear system divides the torque
between the axle shafts. It allows the axle shafts to
rotate 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.
OPERATION
In operation, power flow occurs as follows:
²The pinion gear rotates the ring gear
²The ring gear (bolted to the differential case)
rotates the case
²The differential pinion gears (mounted on the
pinion 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.
38).
When turning corners, the outside wheel must
travel a greater distance than the inside wheel 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
allows the axle shafts to turn at unequal speeds (Fig.
39). In this instance, the input torque applied to the
pinion gears is not divided equally. The pinion gears
Fig. 35 High Speed Latch Engaged
1 - CAGE FORCE EXERTED BY ROLLERS AT HIGH SPEED
Fig. 36 BOC Operation at High Speed with High
Speed Latch
Fig. 37 BOC Input Shaft
1 - GROOVED AREA (2 LOCATIONS)
2 - ROLLER MATING SURFACE
RSREAR DRIVELINE MODULE3-39
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
Page 139 of 2585

now rotate 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.
FLUID - DIFFERENTIAL
ASSEMBLY
STANDARD PROCEDURE - DIFFERENTIAL
ASSEMBLY FLUID CHANGE
The drain plug (Fig. 40) for the differential assem-
bly is located in the bottom of the differential assem-
bly case, toward the rear of the unit.
The fill plug (Fig. 41) for the differential assembly
is located on the rear of the assembly case.The correct fill level is to the bottom of the fill plug
hole. Be sure the vehicle is on a level surface, or is
hoisted in a level manner, in order to obtain the cor-
rect fill level.
(1) Raise the vehicle on a hoist.
(2) Position a drain pan under the differential
drain plug (Fig. 40).
(3) Remove the drain plug and allow the fluid to
drain into the pan.
(4) Install the drain plug and torque to 35 N´m (26
ft. lbs.).
Fig. 38 Differential OperationÐStraight Ahead
Driving
1 - IN STRAIGHT AHEAD DRIVING EACH WHEEL ROTATES AT
100% OF CASE SPEED
2 - PINION GEAR
3 - SIDE GEAR
4 - PINION GEARS ROTATE WITH CASE
Fig. 39 Differential OperationÐOn Turns
1 - PINION GEARS ROTATE ON PINION SHAFT
Fig. 40 Differential Drain Plug
1 - DIFFERENTIAL DRAIN PLUG
Fig. 41 Differential Fill Plug
1 - DIFFERENTIAL FILL PLUG
3 - 40 REAR DRIVELINE MODULERS
DIFFERENTIAL ASSEMBLY (Continued)
Page 140 of 2585

(5) Re-position the drain pan under the differential
fill plug.
(6) Remove the differential fill plug (Fig. 41).
(7) Using a suction gun (Fig. 42) or equivalent, fill
the differential assembly with 0.7 L (1.48 pts.) of
MopartGear and Axle Lubricant (80W-90).
(8) Install the fill plug and torque to 35 N´m (26 ft.
lbs.).
FLUID - OVERRUNNING
CLUTCH HOUSING
STANDARD PROCEDURE - OVERRUNNING
CLUTCH HOUSING FLUID CHANGE
(1) Raise vehicle on hoist.
(2) Position a drain pan under overrunning clutch
housing drain plug.
(3) Remove overrunning clutch housing drain plug
and drain fluid (Fig. 43).
(4) Install the drain plug and torque to 30 N´m (22
ft. lbs.).
(5) Re-position the drain pan under the overrun-
ning clutch housing fill plug.
(6) Remove fill plug (Fig. 44).
(7) Using a suction gun (Fig. 45), add 0.58 L (1.22
pts.) of MopartATF+4 (Automatic Transmission Flu-
idÐType 9602).
(8) Install fill plug and torque to 30 N´m (22 ft.
lbs.).
VISCOUS COUPLER
DESCRIPTION
The heart of the all-wheel drive system is the
inter-axle viscous coupling and bi-directional over-
running clutch. Under normal driving the vehicle
retains predominantly front wheel drive characteris-
tics. The all-wheel drive takes effect when the front
wheels start to slip. Under normal level road,
straight line driving, 100% of the torque is allocated
to the front wheels. The viscous coupler allows more
Fig. 42 Filling Differential
1 - DIFFERENTIAL ASSEMBLY
2 - SUCTION GUN
Fig. 43 Overrunning Clutch Case Drain Plug
1 - OVERRUNNING CLUTCH HOUSING DRAIN PLUG
Fig. 44 Overrunning Clutch Housing Fill Plug
1 - OVERRUNNING CLUTCH HOUSING FILL PLUG
2 - FUEL TANK
RSREAR DRIVELINE MODULE3-41
FLUID - DIFFERENTIAL ASSEMBLY (Continued)
Page 143 of 2585

TORQUE ARM
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove rear driveline module assembly. (Refer
to 3 - DIFFERENTIAL & DRIVELINE/REAR DRIV-
ELINE MODULE - REMOVAL)
(3) Remove six torque arm-to-differential assembly
bolts (Fig. 47). Remove torque arm.
INSTALLATION
(1) Install six torque arm-to-differential assembly
bolts (Fig. 47) and torque to 60 N´m (44 ft. lbs.).
(2) Install rear driveline module assembly. (Refer
to 3 - DIFFERENTIAL & DRIVELINE/REAR DRIV-
ELINE MODULE - INSTALLATION)
(3) Lower vehicle.
INPUT FLANGE SEAL
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove propeller shaft. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/PROPELLER SHAFT -
REMOVAL)
(3) Using tool 6958, remove input flange nut and
washer (Fig. 48).
(4) Remove input flange (Fig. 49).(5) Using suitable screwdriver, remove input
flange seal from overrunning clutch housing (Fig.
50).
Fig. 47 Torque Arm Fasteners
1 - TORQUE ARM ASSEMBLY
2 - BOLT (SIX)
Fig. 48 Input Flange Nut
1 - INPUT FLANGE
2 - TOOL 6958
Fig. 49 Input Flange
1 - INPUT FLANGE/SHIELD
3 - 44 REAR DRIVELINE MODULERS
Page 144 of 2585

INSTALLATION
(1) Using tool 8802, install input flange seal to
overrunning clutch case (Fig. 51).
(2) Install input flange (Fig. 52).
(3) Install flange nut and washer. Using tool 6958,
torque flange nut to 135 N´m (100 ft. lbs.) (Fig. 53).
(4) Install propeller shaft. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/PROPELLER SHAFT -
INSTALLATION)
(5) Lower vehicle.
OUTPUT FLANGE SEAL
REMOVAL
(1) Raise vehicle on hoist.
(2) Remove rear halfshaft inner joint at differen-
tial output flange (Fig. 54).
(3) Using two screwdrivers and wood blocks to pro-
tect differential housing casting, pry output flange
out of differential (Fig. 55).
(4) Use suitable screwdriver to remove output
flange seal (Fig. 56).
Fig. 50 Input Flange Seal Removal
1 - INPUT FLANGE SEAL
2 - SCREWDRIVER
Fig. 51 Input Flange Seal Installation
1 - TOOL 8802
2 - HAMMER
Fig. 52 Input Flange
1 - INPUT FLANGE/SHIELD
Fig. 53 Input Flange Nut
1 - INPUT FLANGE
2 - TOOL 6958
RSREAR DRIVELINE MODULE3-45
INPUT FLANGE SEAL (Continued)
Page 145 of 2585
INSTALLATION
(1) Install output flange seal to differential hous-
ing using tool C4171A and 8493 (Fig. 57).
Fig. 54 Inner Half Shaft Bolts
1 - SHAFT
2 - FLANGE
Fig. 55 Output Flange Removal
1 - WOOD BLOCK
2 - PRYBAR
3 - OUTPUT SHAFT
4 - PRYBAR
5 - WOOD BLOCK
6 - DIFFERENTIAL CASE
Fig. 56 Output Flange Seal Removal
1 - OUTPUT FLANGE SEAL
2 - SCREWDRIVER
Fig. 57 Output Flange Seal Installation
1 - DRIVER HANDLE C4171
2 - INSTALLER 8493
3 - 46 REAR DRIVELINE MODULERS
OUTPUT FLANGE SEAL (Continued)
Page 146 of 2585
(2) Install ouput flange to differential assembly.
Verify that it is seated all the way into position by
attempting to pull out by hand.
(3) Install rear halfshaft inner joint to output
flange.
(4) Install and torque bolts to 61 N´m (45 ft. lbs.)
(Fig. 58).
(5) Check differential assembly fluid level and
adjust as required. (Refer to 3 - DIFFERENTIAL &
DRIVELINE/REAR DRIVELINE MODULE/FLUID -
STANDARD PROCEDURE)
Fig. 58 Inner Half Shaft Bolts
1 - SHAFT
2 - FLANGE
RSREAR DRIVELINE MODULE3-47
OUTPUT FLANGE SEAL (Continued)