GMC 1990 Light Truck Repair Manual page 180

4B4-6 101 / 2-INCH RING GEAR
2. Outer pinion bearing cup (6) using J 8608 and
J 8092.
3. Inner pinion bearing cup (13) using J 24432 and
J 8092.
4. A new collapsible spacer (12) to the pinion.
5. Pinion (14) into the pinion gage (10).
6. Pinion outer bearing (6) onto the pinion.
• Press the bearing onto the pinion.
7. Pinion oil seal (5) using J 24434 and J 8092.
8. Pinion flange oil deflector (4) and pinion flange (3) to
the pinion splines.
9. Washer (2) and a new pinion nut (1).
• Place the pinion cage assembly into the vice.
10. Flange holder J 8614-01 to the pinion flange.
Tighten (Figure 11)
• The nut until the pinion end play is just taken
up. Rotate the pinion while tightening in order
to seat the bearings. Once there is no end play
in the pinion, the preload torque should be
checked.
• Remove J 8614-01. Using an inch-pound
torque wrench, check the pinion preload by
rotating the pinion with the wrench. Preload
should be at or below 2.8 to 4.0 N m (25 to 35
in. lbs.) for new bearings, or 0.56 to 1.7 N m
(5-15 in. lbs.) for used bearings (figure 12).
• If the preload torque is below the preloads
given above, continue torquing the nut in small
increments. Check the preload after each
tightening. Each tightening increases the
bearing preload by several pounds. If the
bearing preload is exceeded, the pinion will
have to be removed, and a new collapsible
spacer installed.
• Once the preload has been obtained, rotate
the pinion several times to assure that the
bearings have seated. Recheck the preload,
and adjust if necessary.
11. Pinion cage (10) to the axle housing. Refer to
" Pinion Installation" in this section.
PINION INSTALLATION
Install or Connect
Tools Required:
J 34943 Pinion Pilot Bearing Installer
J 8092 Driver Handle
Pinion pilot bearing (15) using J 34943 and J 8092
(figure 13).
• Bolt the guide plate to the axle housing.
• Place the bearing (15) onto the guide.
• Drive the bearing into the housing. The part
number of the bearing must face the pinion
flange.
Measure the pinion bearing shims (11). If a new
pinion and ring gear set is installed, the pinion
bearing shim pack must be adjusted.
Examine the heads of the new and old drive pinions.
Compare these codes, and adjust the pinion
bearing shim pack accordingly. The chart in figure
14, shows the proper adjustment to be made to the
shim pack.
Pinion service shims are available in sizes from
0.006 to 0.024-inch.
If the original pinion is being used, the original
pinion shims should also be used.
Pinion bearing shims (11) to the pinion cage.
• The shims, housing, and cage must be clean.
The pinion cage (10) to the axle housing (figure 15).
Cage bolts (7).
a Tighten
• The bolts to 88 N m (65 ft. lbs.).
DIFFERENTIAL CASE ASSEMBLY
Install or Connect (Figure 1)
Tools Required:
J 24429 Side Bearing Adjustment Spanner
J 8092 Driver Handle
J 8107 Side Bearing Puller Plug
• Lubricate all parts with rear axle lubricant.
1. Differential pinion gears (32) and thrust washers (31)
to the spider (33).