Jeep 1987 Wrangler Workshop Manual page 955

REAR AXLE
TRAC-LOK DIFFERENTIAL OVERHAUL
Correct backlash is between 0.13 and 0.23 mm
(0.005 and 0.009 in). However, the optimum
backlash setting is 0.20 mm (0.008 in).
Record the dial indicator reading and remove
indicator set J 8001.
Remove the differential assembly from the axle
housing.
Remove the differential bearings and end play
shims. Do not intermix the shims. Tag them for
reference if necessary.
If backlash is within specified tolerance, pro-
ceed to Differential Bearing Preload
Adjustment.
If backlash is not within specified tolerance, ad-
just backlash as follows:
• To increase backlash, use a thinner shim
pack on the ring gear side of the case. To do
this, subtract the amount needed from the
ring gear shim pack. Then add the same
amount to the opposite shim pack.
• To decrease backlash, use a thicker shim
pack on the ring gear side of the case. To do
this, add the amount needed to the ring gear
shim pack. Then subtract the same amount
from the opposite shim pack.
NOTE: The total (or combined) thickness of
both shim packs does not change. The amount
required for desired backlash is simply trans-
ferred from one side to the other as needed.
For example, if measured backlash is 0.28 mm
(0.011 in) and the optimum setting of 0.20 mm
(0.008 in) is desired, backlash must be de-
creased by 0.076 mm (0.003 in). To do this, add
0.076 mm (0.003 in) to the ring gear shim pack
and subtract the same amount from the oppo-
site shim pack.
Assemble the neccessary shim packs and pro-
ceed to Differential Bearing Preload Adjust-
ment. Do not install the bearings at this time.
Differential Bearing Preload Adjustment
NOTE: Before installing the differential, the dif-
ferential bearings must be preloaded to com-
pensate for heat and loads during operation.
Install the differential bearing shim packs on the
case.
Add one additional 0.10 mm (0.004 in) shim to
each shim pack.
Install the differential bearings with tools J 8092
and J 21784.
Differential Installation
Lightly lubricate the differential bearings, cups,
gears and thrust washers with axle lubricant.
Install the bearing cups on the differential
bearings.
Install the differential in the axle housing. Tap
the outer edges of the differential bearing cups
(8) with a rawhide mallet to seat them in the
housing.
H-41