GMC 1990 Light Truck Repair Manual page 236

4B7-8 LOCKING DIFFERENTIALS
8
. Pull the pinion gear firmly into its seat, and rotate
the gear back and forth while reading the dial
indicator. Record the reading.
• Do not unseat the pinion yoke. This will make the
backlash reading inaccurate.
8
9. Repeat steps 5 - on the other
the readings.
10. The backlash should be between 0.254 and 0.457
0.010
mm ( and 0.018-inch).
11. If the backlash is too high, use a thicker thrust
washer.
12. If the backlash is too low, use a thinner thrust
washer.
Left Side Gear Backlash Adjustment
1. Assemble the clutch plates.
• Alternate the plates as shown in figure 12.
2. Assemble the guide clips (47) to the plates.
• Use grease in the clips to hold them in place
on the plates.
3. Install the thrust washer (45), clutch plate assembly
(44), and left side gear to the differential.
4. Clamp the side gear in place using a set of washers,
a nut, and a bolt long enough to hold the side gear
in place (figure 13).
Place the pinion gears and thrust washers on the
pinion yoke.
Install the yoke firmly to the differential case half.
Loosen the nut, and index one pinion gear tooth to
point downward (perpindicular to the case half face).
Tighten the nut.
Mount a dial indicator on the case half face using a
8
.
magnetic base (figure 15).
9. Place the stem of the dial indicator on the pinion
gear tooth.
10 Pull the pinion gear firmly into its seat, and rotate
.
the gear back and forth while reading the dial
indicator. Record the reading.
Do not unseat the pinion yoke. This will make the
backlash reading inaccurate.
11 . Repeat steps 7 - 10 on the other 2 pinions. Record
the readings.
The backlash should be between 0.051 and 0.254
12
.
0.002 0 010
mm ( and . -inch).
13. If the backlash is too high, use a thicker thrust
washer.
14. If the backlash is too low, use at thinner washer.
Reaction Block Clearance Adjustment
|-»<-| Install or Connect
1. Left thrust washer, plates and side gear. Bolt them
into position. Refer to "Left Side Gear Backlash
Adjustment".
2. Right thrust washer and cam assembly. Bolt them
into position. Refer to "Right Side Gear Backlash
Adjustment".
• Measure the distance from the side gear face to the
case half face (figure 16).
• The thickness of the straight edge must be
subtracted from the reading.
• Add the measurement of both sides together. This is
the side gear spread.
2
pinions. Record
• Measure the thickness of the original reaction
• If the reaction block thickness is not 0.000 to
ASSEMBLY OF THE DIFFERENTIAL
-► 4-
1. Right thrust washer.
2. Right cam unit. Refer to "Cam Unit Assembly".
3. Reaction blocks (41), pinion yoke (42), pinion gears
4. Left thrust washer (45).
Figure 16—Side Gear Spread
blocks together (figure 17).
0.006-inch less than the side gear spread, adjust the
clearance by:
— Selecting new reaction blocks of the correct
thickness to obtain
clearance.
— Reshiming the left and/or right clutch disk
pack. The backlash must remain 0.002 -
010
-. -inch.
Install or Connect (Figure 9)
(39), and pinion thrust washers (38).
• Assemble the plates as shown in figure 9 and
12
.
0.000
to 0.006-inch