Jeep 1997 Grand Cherokee Service Manual page 151

TORQUE WRENCH
SPECIAL TOOL 6790 WITH BOLT IN CENTER HOLE
ZG
DIAGNOSIS AND TESTING (Continued)
TRAC–LOK TEST
WARNING: WHEN SERVICING VEHICLES WITH A
TRAC–LOK DIFFERENTIAL DO NOT USE THE
ENGINE TO TURN THE AXLE AND WHEELS. BOTH
REAR WHEELS MUST BE RAISED AND THE VEHI-
CLE SUPPORTED. A TRAC–LOK AXLE CAN EXERT
ENOUGH FORCE IF ONE WHEEL IS IN CONTACT
WITH A SURFACE TO CAUSE THE VEHICLE TO
MOVE.
The differential can be tested without removing the
differential case by measuring rotating torque. Make
sure brakes are not dragging during this measure-
ment.
(1) Place blocks in front and rear of both front
wheels.
(2) Raise one rear wheel until it is completely off
the ground.
(3) Engine off, transmission in neutral, and park-
ing brake off.
(4) Remove wheel and bolt Special Tool 6790 to
studs.
(5) Use torque wrench on special tool to rotate
wheel and read rotating torque (Fig. 5).
Fig. 5 Trac-lok Test —Typical
(6) If rotating torque is less than 22 N·m (30 ft.
lbs.) or more than 271 N·m (200 ft. lbs.) on either
wheel the unit should be serviced.
SERVICE PROCEDURES
LUBRICANT CHANGE
(1) Raise and support the vehicle.
(2) Remove the lubricant fill hole plug from the
differential housing cover.
(3) Remove the differential housing cover and
drain the lubricant from the housing.
AXLE HOUSING COVER
SEALANT
DIFFERENTIAL AND DRIVELINE
(4) Clean the housing cavity with a flushing oil,
light engine oil, or lint free cloth. Do not use water,
steam, kerosene, or gasoline for cleaning.
(5) Remove the original sealant from the housing
and cover surfaces.
(6) Apply a bead of Mopar Silicone Rubber Seal-
ant, or equivalent, to the housing cover (Fig. 6).
Fig. 6 Apply Sealant
Install the housing cover within 5 minutes
after applying the sealant.
(7) Install the cover and any identification tag.
Tighten the cover bolts to 41 N·m (30 ft. lbs.) torque.
(8) For Trac–lok
Mopar Trac–lok lubricant (friction modifier), or
equivalent, must be added after repair service or a
lubricant change. Refer to the Lubricant Specifica-
tions section of this group for the quantity necessary.
(9) Fill differential with Mopar
Lubricant, or equivalent, to bottom of the fill plug
hole. Refer to the Lubricant Specifications section of
this group for the quantity necessary.
CAUTION: Overfilling the differential can result in
lubricant foaming and overheating.
(10) Install the fill hole plug and lower the vehicle.
(11) Trac–lok differential equipped vehicles should
be road tested by making 10 to 12 slow figure-eight
turns. This maneuver will pump the lubricant
through the clutch discs to eliminate a possible chat-
ter noise complaint.
REMOVAL AND INSTALLATION
REAR AXLE
REMOVAL
(1) Raise and support the vehicle.
differentials, a quantity
Hypoid Gear
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