GMC 1990 Light Truck Repair Manual page 325

Figure 19— Installing the Pinion Bearing
Figure 21—Measuring Pinion Bearing Preload
PINION INSTALLATION
Tools Required:
J 33785 Bearing Installer
J 8614-01 Pinion Flange Remover
J 33782 Seal Installer
L-VAN FRONT AXLE 4C5-9
1. Shim (38) to the pinion gear (37).
• The shim must be of the proper size, as select­
ed previously.
2. Bearing (39) onto the pinion gear (37) using
J 33785 (figure 19).
3. New spacer (40) onto the pinion gear (37).
4. Bearing (41) into the case.
5. Seal (42) into the case using J 33782 (figure 20).
6. Pinion gear, with bearing and spacer, to the case.
7. Deflector (43), flange (44), washer (45) and nut
(46).
• Apply PST sealant (GM part number 1052080
or equivalent) to the pinion gear threads and
on both sides of the washer.
• Tighten nut (46) until no end play is detectable
while holding the flange (44) with J 8614-01
(figure 9).
• No further tightening should be attempted until
F1789
bearing preload has been checked.
Measure
• Pinion bearing preload. Use an inch pound torque
wrench (figure 21). The correct preload is 1.7-2.8
N-m (15-25 in. lbs.).
1. Rotate the pinion with the torque wrench and
observe the reading.
2. If the preload torque is below specifications, con­
tinue torquing the pinion nut in small increments.
Check the preload after each tightening. Each
tightening increases the bearing preload by sever­
al inch pounds. If the bearing preload is exceed­
ed, the pinion will have to be removed, and a new
collapsible spacer installed.
3. Once the preload has been obtained rotate the
pinion several times to make sure that the bear­
ings have seated. Recheck the preload, and
adjust if necessary.
DIFFERENTIAL ASSEMBLY
E3
Install or Connect (figures 1, 2, 22, 23 and 24)
Tools Required
J 33788 Bearing Installer
J 23423-A Bearing Cup Installer
J 33792 Side Bearing Adjuster Wrench
1. Bearing (30) into the sleeve (32) using J 33788
(figure 22).
2. Sleeves (32) into the carrier case (29). Thread in
all the way.
3. Side bearing cups (33) into the carrier case (29)
using J 23423-A.
4. Differential assembly to the carrier case.
• Place the differential case assembly (35) into
the carrier case half which contains the pinion
gear.
• Turn the left sleeve (32) in toward the differen­
tial case using J 33792 until backlash is felt
between the ring and pinion gear.
5. Carrier case halves (29). Do not use any sealer at
this time.
• If the carrier halves do not make complete con­
tact, back out the right hand adjusting sleeve
(32). Use J 33792 (figure 23).
INSTALLATION