Chevrolet 1973 Overhaul Manual page 91

4 - 6 0 REAR AXLE DIFFERENTIAL CARRIER
J—24384
Fig. 1 IF —In s ta llin g Pinion Oil Seal
DIFFERENTIAL CASE
Installation and Adjustment
1. Place the differential case, with side bearings and
cups installed, into position in the carrier.
2. Select the smallest of the original shims as a
"gauging" shim and place it between the bearing
cup and the carrier on the ring gear side of the
case.
3. Install bearing caps and bearing screws finger tight.
Make sure bearing caps are in correct marked
position.
4. Mount a dial indicator on the ring gear side of the
carrier, with the indicator probe in contact with the
back face of the ring gear.
5. Position two screwdrivers between the bearing cup
and the carrier on the side opposite the ring gear.
6. Pull on the screwdrivers and force the differential
case as far as possible toward the indicator. With
force still applied, set the dial indicator to zero.
7. Reposition the screwdrivers on the ring gear side of
the case. Force the ring gear into mesh with the
drive pinion and observe the dial indicator. Repeat
this operation several times until the same reading
is obtained.
8. Add the indicator reading to the "gauging" shim
thickness to determine the correct shim dimension
for installation on the ring gear side of the case.
For example, if the gauging shim was .155 inch, and
the indicator reading in step 7 was .017 inch, the
correct shim would be .155 + .017 = .172 inch.
9. Remove the "gauging" shim and install the correct
size shim into position between the bearing cup and
the carrier on the ring gear side of the case.
10. To determine the correct dimension for the
remaining shim, first refer to the dimension
obtained in step 8 of "Gauging Procedures—Side
Bearing Shims". From that figure, subtract the size
of the shim installed in step 9 above; then add .006
inch for preload and backlash.
For example, if the reading in step 18 was .329 inch,
and the shim just installed on the ring gear side of
the case was .172 inch, the correct shim dimension
would be .329 -.172 = .157 + .006 = .163 inch.
11. Spread the differential carrier as shown in figure
2F.
12. Assemble the shim determined in step 10 into place
between the bearing cup and the carrier.
13. Remove the spreader and the dial indicator.
14. Install the bearing caps in marked positions and
torque cap screws to specifications.
15. Install dial indicator and check ring gear backlash
at four equally spaced points around the ring gear.
Backlash must be held to .004" to .009" and must
not vary more than .002" between positions
checked.
16. Whenever backlash is not within limits, differential
bearing shim pack should be corrected to bring
backlash within limits.
a. Low backlash is corrected by decreasing the
shim on the ring gear side and increasing the
opposite side shim
b. High backlash is corrected by increasing the
shim on the ring gear side and decreasing the
opposite side shim
17. Check gear tooth contact, using yellow lead method,
as described in "Gear Tooth Contact Pattern
Check".
18. Using a new gasket, install housing cover and
torque bolts to specifications.
19. Reinstall the rear universal joint, and torque "U "
bolt nuts to specifications.
20. Install axles into carrier and axle flange over hub
studs.
21. Torque hub stud nuts to specifications.
22. Fill differentia] with lubricant.
23. Install wheel and tire assembly.
CHECKS AND ADJUSTM ENTS
Four adjustments are essential for proper operation of
the differential and its related parts. These adjustments
are a) Pinion Bearing Preload, b) Side Bearing Preload,
c) Pinion Depth and d) Ring Gear-to-Pinion Backlash.
Pinion Bearing Preload is set to specifications in step 12
of "Drive Pinion—Assembly and Installation". Side
Bearing Preload is set to specifications in step 10 of
"Differential Case—Installation and Adjustment". Fol­
lowing service to the Differential Case or to the Drive
Pinion and Ring Gear, a Gear Tooth Contact Pattern
Check be made, to verify the accuracy of the work
must
an equal amount
an equal amount
OVERHAUL MANUAL