Chevrolet 1973 Overhaul Manual page 45

4 - 1 4 REAR AXLE DIFFERENTIAL CARRIER
all ring gear teeth using a medium stiff brush.
When properly used, the area of pinion tooth
contact will be visible when hand load is applied.
3. Tighten bearing cap bolts to 55 lb. ft.
4. Expand brake shoes until a torque of 20-30 lb. ft. is
required to turn the pinion.
NOTE: A test made without loading the
gears will not give a satisfactory pattern.
Turn companion flange with wrench so that
ring gear rotates one full revolution then
reverse rotation so that ring gear rotates one
revolution in opposite direction. Excessive
turning of ring gear is not recommended.
5. Observe pattern on ring gear teeth and compare
with Figure 26A.
Adjustments Affecting Tooth Contact
Two adjustments can be made which will affect tooth
contact pattern. These adjustments are backlash and
position of drive pinion in carrier. The effects of bearing
preloads are not readily apparent on hand loaded teeth
pattern tests; however, these adjustments should be
within specifications before proceeding with backlash
and drive pinion adjustments.
The position of the drive pinion is adjusted by
increasing or decreasing the shim thickness between the
pinion head and inner race of rear bearing. The shim is
used in the differential to compensate for manufacturing
tolerances. Increasing shim thickness will move the
pinion closer to certerline of the ring gear. Decreasing
shim thickness will move pinion farther away from
centerline of the ring gear.
Backlash is adjusted by means of the side bearing
adjusting shims which moves the entire case and ring
gear assembly closer to, or farther from the drive pinion.
Fig. 26A—Gear Teeth Contact Pattern Check
NOTE: It may be necessary to adjust both
pinion depth and backlash to obtain the
correct pattern.
OVERHAUL MANUAL