GMC 1989 Light Duty Truck, Repair Manual, Page: 190 / 998

4B5-2 DANA REAR AXLES
Determine the cause of the axle problem before
disassem bly if possible.
DISASSEMBLY OF THE
REAR AXLE
+ +
R em ove or D isconnect (Figure 1)
Tools Required:
J 24385-01 Differential Housing Spreader
J 29721 Differential Side Bearing Remover
J 29721-70 Side Bearing Adapters
J 8107-3 Side Bearing Puller Plug
J 8614-01 Pinion Flange Holder
• Place the rear axle in a suitable support.
1. The differential cover bolts (17) and the differential
cover (14) (figure 2).
• D ra in th e g e a r lu b ric a n t in to a p ro p e r
container.
2. Axle shafts (38). Refer to the proper service manual.
3. Bearing cap bolts (19) (figure 3).
4. Bearing caps (18).
• The mating letters are stamped on the caps
and the axle housing. The caps are to be
reassembled exactly as removed.
• Assemble J 24385-01 to the differential housing as
shown in figure 4.
• Assemble the dial indicator as shown in figure 4.
Preset the gage at least 0.020-inch, and then rotate
the gage housing to zero the dial.
NOTICE: Do n ot spre ad the differential carrier
m o r e t h a n 0 . 3 8 m m ( 0 . 0 1 5 - i n c h ) .
O v e r - s p r e a d in g th e c a r r ie r ca n d a m a g e or
distort the carrier.
• S p re a d th e c a rrie r w h ile e x a m in in g th e d ia l
indicator. Do not spread the carrier more than 0.38
mm (0.015-inch).
5. Differential case (22) from the carrier (1) using two
pry bars (figure 5).
6. The spreader J 24385-01 from the carrier (1).
7. Bearing cups (20).
• Mark the cups as left and right, and place
them with the proper bearing caps.
8. D iffe re n tia l side b e a rin g s (20) using J 29721,
J 29721-70, and J 8107-3 (figure 6).
• Mark the bearings as left and right, and place
them with the proper bearing caps and cups.
9. Differential shims (21).
• Mark the shims as left or right.
10. Ring gear bolts (23).
• Place shop towels over the vice jaws. Put the
differential case in the vice (figure 7).
NOTICE: Do not pry the ring gear from the case,
th is w i l l d a m a g e t h e r i n g g e a r a n d t h e
differential case.
11. Ring gear (2) from the differential case using a
rawhide hammer.
• Ring gear (2) from the vise.
• Put the differential case in the vise.
12. Lock pin (29) from the differential using a hammer
and a punch (figure 8).
13. Pinion shaft (28) using a hammer and a brass drift
(figure 9).
14. Differential pinion gears (24) and thrust washers
(26).
• Rotate the side gears until the pinion gears
are in the opening of the differential (figure
10
).
15. Differential side gears (25) and thrust washers (27).
• Mark the gears and washers as left and right.
• Replace the carrier cover (14) using two bolts (17) to
keep the pinion from falling to the floor.
Inspect
• Drive pinion bearing preload (figure 11).
• For looseness of the pinion assem bly by
moving it back and forth. (Looseness indicates
excessive bearing wear).
16. Pinion nut (12) and washer (11) using J 8614-01 to
hold the pinion (figure 12).
17. Pinion flange (10) using J 8614-01 (figure 13).
18. Pinion (2) from the carrier using a rawhide hammer
to tap the pinion (figure 14).
19. Carrier cover (14) and the pinion (2).
20. Pinion preload shims (6).
• Keep the shims together on the bench.
21. Pinion seal (9).
22. Pinion outer bearing (7) and oil slinger (8).
23. Bearing cups (3) and (7) from the axle housing using
a hammer and a punch (figure 15).
• Work the cups out of the housing evenly,
moving the punch back and forth between one
side of the cup and the other.
24. Pinion adjusting shims (4) and baffle (5).
• Keep the shims together on the bench.
25. P in io n in n e r b e a rin g (3) u s in g J 29721 and
J 29721-70 (figure 16).
CLEANING
Do not steam clean drive parts having ground and
polished surfaces such as gears, bearings, and shafts.
These parts should be cleaned in a suitable solvent. All
parts should be disassembled before cleaning.
Parts should be thoroughly dried imm ediately after
cleaning. Use soft, clean, lintless rags. Parts may be dried
with compressed air. Do not allow the bearings to spin
while drying them with compressed air.
INSPECTION
It is very important to carefully and thoroughly inspect
all drive unit parts before reassembly.
Thorough inspection of the drive parts for wear or
stress and subsequent replacement of worn parts will
eliminate costly drive com ponent repair after reassembly.