GMC 1990 Light Truck Repair Manual page 265

• Add shims to increase the preload.
ASSEMBLING THE
DIFFERENTIAL TO
THE AXLE HOUSING
Tools Required:
J 23690 Differential Side Bearing Installer
J 8092 Driver Handle
J 24385-01 Differential Carrier Spreader
1. Assemble the differential case (22) with master
bearings installed to the axle housing. The pinion
must be installed.
2. Mount a dial indicator having a minimum travel of 5
mm (0.200-inch) with a magnetic base on the ring
gear bolt side of the housing (figure 37).
3. Place the indicator tip on the chalk mark made
earlier.
4. Force the ring gear into mesh with the pinion. Rock
the ring gear to allow the teeth of the gears to mesh.
9 /4-INCH RING GEAR FRONT AXLE 4C2-13
3
Figure 38—Installing the Differential Bearings
5. With the force still applied to the differential case,
set the dial indicator to zero.
6. Force the differential case away from the pinion
gear to obtain an indicator reading. Repeat this
action until a consistent reading is obtained. This
will be the size of the left shim pack.
7. Remove the indicator and the differential case from
the carrier.
8. Remove the master bearings from the differential
case.
9. Using the total shim pack size determined earlier,
(Refer to " Determining Total Differential Shim Pack
Size" in this section) subtract the reading found in
step 6 from the total reading. The reading found in
step 6 will be the shim size on the ring gear side.
The remaining portion of the shim pack will be used
on the side opposite the ring gear. Add an additional
0.38 mm (0.015-inch) of shims to the side opposite
the ring gear to preload the bearings.
10. Place the proper shims on the differential side
bearing hub (ring gear side) and drive the
differential bearing onto the hub using J 23690 and
J 8092 (figure 38).
11. Place the proper shims on the differential side
bearing hub (opposite the ring gear) and drive the
differential bearing onto the hub using J 23690 and
J 8092 (figure 38).
12. Assemble J 24385-01 to the axle housing as shown
in figure 39.
13. Assemble the dial indicator as shown in figure 39.
Preset the gage at least 5 mm (0.020-inch), and then
rotate the indicator housing to zero the dial.
NOTICE: Do not spread the differential carrier
more
Over-spreading the carrier can damage or
distort the carrier.
14. Spread the carrier while exam ining the dial
indicator.
15. Remove the dial indicator.
16. Place the bearing cups (20) onto the bearings.
17. Install the differential assembly into the carrier.
than 0.38 mm (0 .0 1 5-inch).