Chevrolet 1991 Light Duty Truck Repair Manual page 212

4B7-8 LOCKING DIFFERENTIAL
7. Place the stem of the dial indicator on the pinion
gear tooth.
8. Pull the pinion gear firmly into its seat, and rotate
the gear back and forth while reading the dial indi­
cator. Record the reading.
• Do not unseat the pinion yoke. This will make the
backlash reading inaccurate.
9. Repeat steps 5 - 8 on the remaining 2 pinions.
Record the readings.
10. The backlash should be between 0.254 and 0.457
mm (0.010 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 Adjustm ent
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 assem­
bly (44), and left side gear to the differential.
4. Ciamp the side gear in place using a set of wash­
ers, a nut, and a bolt long enough to hold the side
gear in place (figure 13).
5. Place the pinion gears and thrust washers on the
pinion yoke.
6. Install the yoke firmly to the differential case half.
7. Loosen the nut, and index one pinion gear tooth to
point downward (perpendicular to the case half
face). Tighten the nut.
8. Mount a dial indicator on the case half face using
a 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 indi­
cator. 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.
12. The backlash should be between 0.051 and 0.254
mm (0.002 and 0.010-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 Adjustm ent
□ 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 sub­
tracted from the reading.
• Add the measurement of both sides together. This
is the side gear spread.
• Measure the thickness of the original reaction
blocks and reaction block thrust washers together
(figure 17).
• If the combined reaction block and thrust washer
thickness is not 0.000 to 0.006-inch less than the
side gear spread, adjust the clearance by:
— Selecting new reaction block thrust washer of
the correct thickness to obtain 0.000 to
0.006-inch clearance.
— Reshimming the left and/or right clutch disc
pack. The side gear backlash must be main­
tained. Refer to "Right Side" and/or "Left Side
Gear Backlash Adjustment" in this section.
ASSEMBLY OF THE DIFFERENTIAL
Install or Connect (Figure 9)
1. Right thrust washer.
2. Right cam unit. Refer to " Cam Unit Assembly" .
3. Reaction blocks (41), reaction block thrust washer,
pinion yoke (42), pinion gears (39), and pinion
thrust washers (38).