Chevrolet 1991 Light Duty Truck Repair Manual page 142

4B3-6 9 1/2-INCH RING GEAR
1. Clean all the gage parts.
2. Lubricate the front and rear pinion bearings with
axle lubricant.
3. Place the bearings (10) and (13) into the pinion
bearing cups.
4. Install J 21777-8, J 21777-42, J 21777-85 and
J 21777-43 to the pinion bore (figure 12).
5. Hold the stud stationary at the flats of the stud.
[1 5 ] Tighten
• Stud nut to 2.2 N m (20 in. lbs.).
6. Rotate the gage plate and bearings several com­
plete revolutions to seat the bearings.
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 21777-86, J 21777-1 Arbor, and J 8001
to the differential bearing bore as shown in figure
13.
• 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 gag­
ing 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 3/4 of a turn to the right. Tighten the
dial indicator in this postion (figure 14).
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 indi­
cator 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.
Figure 12—Gage Plate Tools
16. Record the actual number on the dial indicator and
not the number which represents how far the nee­
dle 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 posi­
tion for the pinion from the nominal setting.
• If the pinion is stamped with a plus number,
add that many thousandths to the nominal set­
ting. If the nominal setting is 0.033-inch and
the pinion is marked +2, the correct shim
depth would be 0.033-inch + 0.002-inch = 0.
035-inch.
• If the pinion is stamped with a minus number,
subtract that many thousandths from the nomi­
nal setting. If the nominal setting is 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 (6) to the pinion
according to this procedure.
PINION INSTALLATION
0 Install or Connect
Tools Required:
J 22388 Pinion Oil Seal Installer
J 22804-1 Pinion Oil Seal Spacer
J 5590 Rear Pinion Bearing Cone Installer
• The bearing cups should have been installed in
" Pinion Depth Adjustment" in this section.