GMC 1989 Light Duty Truck Repair Manual page 154

8
4B2-6 1 / 2-INCH RING GEAR
Figure 11—Gage Plate Tools
7. Tighten the stud nut until a torque of 1.6 to 2.2 N m
(15 to 25 in. lbs.) is obtained to keep the gage plate
in rotation.
8
. Assemble J 21777-45, J 21777-1 Arbor, and J 8001 to
the differential bearing bore as shown in figure
• The bearing bores must be clean and burr
free.
9. Install the side bearing caps, and tighten the bolts
finger tight.
10. Rotate the gage plate until the proper gaging area is
parallel with the disks.
11. Position the gage shaft assembly in the carrier so
that the dial indicator rod is centered on the gage
area of the gage block.
12. Set the dial indicator at zero. Push the indicator
down on the indicator shaft until the needle rotates
approximately 3U of a turn to the right. Tighten the
dial indicator in this postion.
13. Rotate the gage shaft slowly back and forth until the
dial indicator reads the greatest deflection (when the
indicator needle is centered between movement to
the left and to the right).
14. At the point of greatest deflection, set the dial
indicator to zero. Repeat the rocking action of the
gage shaft to verify the zero setting.
15. Rotate the gage shaft until the dial indicator rod
does not touch the gage block.
16. Record the actual number on the dial indicator and
not the number which represents how far the needle
travels. This is the nominal pinion setting.
EXAMPLE: If the indicator needle moved to the left
1.70 mm (0.067-inch) to a dial reading of 0.84 mm
(0.033-inch) as shown in figure 13, record the dial
reading of 0.84 mm (0.033-inch) not 1.70 mm
(0.067-inch).
17. Check the pinion face for a pinion adjustment mark.
This mark indicates the best running position for the
pinion from the nominal setting.
• If the pinion is stamped with a plus number,
add that many thousandths to the nominal
setting. If the nominal setting is 0.033-inch and
the pinion is marked +
depth would be 0.033-inch + 0.002-inch =
0.035-inch.
• If the pinion is stamped with a minus number,
subtract that many th ou san d ths from the
nom inal setting. If the nom inal setting is
12 .
0.033-inch and the pinion is marked -2, the
correct shim depth would be 0.033-inch -
0.002-inch = 0.031-inch.
• If the pinion has no plus or minus marked on
the pinion, use the nominal pinion setting to
select a shim.
18. Remove bearing caps (10) and depth gaging tools.
19. Install the correct pinion shim (
according to this procedure.
PINION INSTALLATION
-►+ Install or C onnect
Tools Required:
J 8809-01 Rear Pinion Bearing Cone Installer
J 22388 Pinion Oil Seal Installer
J 8614-01 Pinion Flange Remover
J 5590 Rear Pinion Bearing Cone Installer
• The bearing cups should have been installed in
" Pinion Depth Adjustm ent" in this section.
1. The pinion inner bearing (5) using J 8609-01.
• Press the bearing onto the pinion until the
bearing cone seats on the pinion shims.
A new collapsable spacer (4).
Lubricate the pinion bearings with axle lubricant.
Pinion (7) to the axle housing.
Outer pinion bearing (39) onto the pinion using
J 5590.
• Hold the pinion forward from inside the case
while driving the bearing onto the pinion.
Pinion oil seal (38) using J 22388 (figure 14).
Pinion flange (37) to the pinion by tapping it with a
rawhide hammer until a few threads show through
the pinion flange.
7. Pinion washer (36) and a new nut (35) while holding
the pinion flange with J 8614-01 (figure 15).
2 , the correct shim
6 ) to the pinion