GMC 1989 Light Duty Truck Repair Manual page 238

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 2 pinions. Record
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.
If the backlash is too low, use a thinner thrust
12
washer.
Left Side Gear Backlash Adjustment
1 Assemble the clutch plates.
• Alternate the plates as shown in figure 12.
Assemble the guide clips (47) to the plates.
2
.
• Use grease in the clips to hold them in place
on the plates.
Install the thrust washer (45), clutch plate assembly
3.
(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.
Repeat steps 7 - 10 on the other 2 pinions. Record
11
.
the readings.
12. The backlash should be between 0.051 and 0.254
0.002 0 010
mm ( and . -inch).
If the backlash is too high, use a thicker thrust
13.
washer.
14. If the backlash is too low, use at thinner washer.
Reaction Block Clearance Adjustment
Install or C onnect
1. Left thrust washer, plates and side gear. Bolt them
into position. Refer to "Left Side Gear Backlash
Adjustm ent".
2. Right thrust washer and cam assembly. Bolt them
into position. Refer to "R ight Side Gear Backlash
Adjustm ent".
• Measure the distance from the side gear face to the
case half face (figure 16).
• The th ic k n e s s of the s tra ig h t edge m ust be
subtracted from the reading.
• Add the measurement of both sides together. This is
the side gear spread.
• M easure the thickness of the original reaction
blocks together (figure 17).
• If the reaction block th ickness is not 0.000 to
0.006-inch less than the side gear spread, adjust the
clearance by:
— Selecting new reaction blocks of the correct
th ic k n e s s to o b ta in
clearance.
— Reshiming the left and/or right clutch disk
pack. The backlash m ust rem ain 0.002 -
010
-. -inch.
ASSEMBLY OF THE DIFFERENTIAL
4 4
Install or C onnect (Figure 9)
■ -
1. Right thrust washer.
2. Right cam unit. Refer to "Cam Unit Assem bly".
3. Reaction blocks (41), pinion yoke (42), pinion gears
(39), and pinion thrust washers (38).
4. Left thrust washer (45).
• Assemble the plates as shown in figure 9 and
12
.
0.000
to 0 .00 6-inch