Chevrolet 1988 Light Duty Truck Repair Manual page 146

4B1-6 7 AND 7s/8-INCH RING GEAR AXLES
1/2
T ig h ten
• Stud nut to 2.2 N m (20 in. lbs.).
6. R o ta te th e g a g e p la te and b e a rin g s se ve ra l
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. Assem bly J 21777-45, J 23597-11, and J 8001 to the
differential bearing bores as shown in figure 9.
• The bearing bores must be clean and burr
free.
9. Install the side bearing caps ana tighten the bolts
finger tight.
10. Rotate the gage plate until the gaging areas are
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
approxim ately of a turn to the right. Tighten the
3U
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 moving 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 num ber on the dial indicator and
not the number w hich 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 10, record the dial
read in g of 0.84 mm (0.033-inch) not 1.70 mm
(0.067-inch).
The dial indicator should be in the 0.50 to the 1.27
mm (0.020 to 0.050-inch) range.
17. Check the pinion face for a pinion adjustm ent 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 stam ped with a minus number,
subtract th a t m any th o u sa n d th s from the
nom inal se ttin g . If the nom inal 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 (31) and depth gaging tools.
19. Install the correct pinion shim (19) according to this
procedure to the pinion.
DIFFERENTIAL CASE ASSEMBLY
+ 2 , the correct shim
Install or C on n ect (F ig u re 1)
Tools Required:
J 25299 Differential Side Bearing Installer
J 8092 Driver Handle
J 8107-2 Differential Side Bearing Remover
Plug
• Lubricate all parts with rear axle lubricant.
1. Side gear thrust washers (28) to the side gears (26).
2. Side gears (28) to the differential case (24).
• Place the side gears in place on the same side
as removed.
3. Pinion gears (28) to the differential w ithout the thrust
washers (27).
• Place one pinion gear onto the side gears and
rotate the gears until the pinion is exactly
opposite from the differential opening.
• Place the second pinion gear onto the side
gears so that the pinion gear holes line up.
• Rotate the pinion gears into place, and veryify
that the pinion gears line up with the pinion
shaft holes.
4. Pinion thrust washers (27).
• Rotate the pinion gears toward the differential
opening just enough to slide in the pinion
thrust washers.
5. Pinion shaft.
6. Pinion shaft screw.
• C heck that the mating surfaces of the differential
case and the ring gear are clean and burr free.
7. Ring gear (20) to the differential case (24) (figure
1 1
).
• Thread two left-hand threaded studs into the
ring gear on opposite sides.
• Place the ring gear onto the case, and align
the studs with the holes in the case.
8. New ring gear bolts (25).
• T ig hten the ring ge ar bolts alte rn a te ly in
stages gradually pulling the ring gear onto the
differential case.
T ig h ten
• The ring gear bolts in sequence to 120 N m
(90 ft. lbs.).
9. D iffe re n tia l side b e a rin g s (22) using J 25299,
J 8092, and J 8107-2 (figure 12).
• Place J 8107-2 into the differential on the side
opposite of bearing installation to protect the
differential case.
• Drive the bearing onto the case using J 25299
and J 8092.
10. Differential case (24) to the axle housing. Refer to
" Side Bearing Pre-Load A d justm en t" in this section.
SIDE BEARING PRE-LOAD ADJUSTMENT
• The side bearing pre-load adjustm ent m ust be
made before installing the pinion.
• The case side bearing pre-load is adjusted by
changing the thickness of both the left and right
sh im s eq ua lly. T h is w ill m a in ta in the o rig in a l
backlash.