Unit R E P A Ir - GMC 1982 Light Duty Truck Service Manual

4 B 1 -6 R EA R A X L E
Fig. 4B1 -16—Installing Pinion Flange
Fig. 4B1-17--Differential Case Removal
Before proceeding with following steps, it is advisable
to check the existing ring gear to pinion backlash as
described under "Operational Checks and A djustm ents"
(Refer to Section 4B). This will indicate gear or bearing
wear or an error in backlash or pinion depth setting which
will help in determining cause of axle noise. Backlash should
be recorded so that if same gears are reused, they may be
reinstalled at original lash to avoid changing gear tooth
contact.
1. Remove screw that retains differential pinion shaft, and
remove pinion shaft.
2. Remove rear axle shafts.
3. Roll out the differential pinions and thrust washers,
then remove side gears and th ru st washers. M a rk
pinions and side gears so that they can be reassembled
in original position.
Permatex Type A or equivalent) prior to installing
washer and nut on pinion.
5. Using J - 8 6 14-11 as shown in figure 4B1-16, install
flange onto pinion. Install washer and nut, and tighten
nut to original position. Refer to scribe marks and
number of exposed threads, recorded earlier.
NOTICE:
pinion shaft. To do so may dam age the ring gear and
pinion.
6. Measure rotating torque of pinion and compare with
torque recorded before removal. Tighten pinion nut in
additional small increments until the torque necessary
to rotate the pinion exceeds the original figure by .1-.6
N-m (1 -5 in. lbs.). Do not exceed the original torque by
more than .6 N-m (5 in. lbs.).
7. R eattach propeller shaft and torque to specifications.
Reinstall brake drums and wheels.
NOTICE:
regarding the fasteners referred to in step 7.
8. Lower vehicle and remove from hoist.
UNIT REPAIR
4. M ark the bearing caps and housing for reassembly in
same position. Loosen bearing cap bolts. T ap surface of
bearing caps to loosen.
NOTICE:
damage machined face of caps.
5. Using a pry bar as shown in figure 4B1-17, pry
differential case out of carrier. Exercise caution in
prying on carrier so that gasket sealing surface is not
damaged. If the bearings are preloaded, the case will
suddenly fall free when it is pried past a certain point;
therefore, m ake sure case is properly supported to
prevent dam age. The bearing caps may be loosely
installed, as shown in figure 4B1-17, to prevent case
from falling.
6. ?Place left and right bearing cups with bearing caps so
that they may be reinstalled in original positions. Place
shims with appropriate cups.
Inspection
1. Clean all parts in cleaning solvent; inspect all bearing
cups, races and rollers for scoring, chipping or evidence
of excessive wear.
2. Inspect axle shaft and side gear splines for evidence of
excessive wear.
3. Inspect hypoid ring gear and pinion teeth for possible
scoring, cracking or chipping.
4. Inspect differential case, pinions side gears, th ru st
washers and pinion shaft for cracks, scoring, spalling or
excessive wear.
5. Check fit of differential side gears in case.
D iffe re n tia l B earing Replacem ent
1. Install Tool J-22888 and A d a p te r Plug J - 8 107-4,
J - 8 107-3 for the 9 1/2" ring gear, assuring puller legs
are fitted securely in notches in case and against
bearing cone, as shown in figure 3B.
2. Tighten puller screw to remove bearing.
Do not attem pt to ham m er the flange onto
See N O T I C E on page 1 of this section
Do not attem pt to pry caps off as this may