GMC 1990 Light Truck Repair Manual page 279

Figure 20—Installing the Pinion Bearing
6. Turn the left adjusting sleeve IN one notch using
J 33792.
7. Rotate the pinion several times to seat the bearings.
8. Install J 34047, J 25025-1 and J 8001-1 (figure 27).
9. Place the indicator stem at the heel end of a tooth.
Figure 22—Measuring Pinion Bearing Preload
J 33785
F-01789
T TRUCK FRONT AXLE 4C3-11
"
Figure 23—Installing the Sleeve Bearing
Figure 24—Adjusting the Sleeve
J 33788
F-01791
F-01781