Jeep 1997 Grand Cherokee Service Manual page 138

DIAL CATOR INDI- FOR MORE BACKLASH INCREASE SHIM THIS SIDE FOR LESS BACKLASH
DECREASE INCREASE SHIM THIS DIE SHIM THIS
SIDE FOR MORE BACK- FOR LESS BACKLASH
LASH
3 - 80 DIFFERENTIAL AND DRIVELINE
ADJUSTMENTS (Continued)
After the proper backlash is achieved, perform the
Gear Contact Pattern Analysis procedure.
Fig. 79 Ring Gear Backlash Measurement
Fig. 80 Backlash Shim Adjustment
FOR MORE BACKLASH
DECREASE SHIM THIS
SIDE FOR LESS BACK-
LASH
GEAR CONTACT PATTERN ANALYSIS
The ring and pinion gear teeth contact patterns
will show if the pinion gear depth is correct in the
axle housing. It will also show if the ring gear back-
lash has been adjusted correctly. The backlash can be
adjusted within specifications to achieve desired
tooth contact patterns.
(1) Apply a thin coat of hydrated ferric oxide, or
equivalent, to the drive and coast side of the ring
gear teeth.
(2) Wrap, twist, and hold a shop towel around the
pinion yoke to increase the turning resistance of the
pinion gear. This will provide a more distinct contact
pattern.
(3) Using a boxed end wrench on a ring gear bolt,
Rotate the differential case one complete revolution
in both directions while a load is being applied from
shop towel.
The areas on the ring gear teeth with the greatest
degree of contact against the pinion gear teeth will
squeegee the compound to the areas with the least
amount of contact. Note and compare patterns on the
ring gear teeth to Gear Tooth Contact Patterns chart
(Fig. 78) and adjust pinion depth and gear backlash
as necessary.
ZG