GMC 1990 Light Truck Repair Manual page 231

CAM UNIT ASSEMBLY - 71 /2 AND 8 V
Install or Connect
1. Cam plate (16) to the cam side gear (21).
2. Wave spring.
3. Clutch plates (71 fe - 75/s —
• Alternate the plates as shown in figure 2.
4. Snap ring.
5. Guide clips (20) to the plates.
• Use grease in the clips to hold them in place
on the plates.
CAM UNIT ASEMBLY - 9 V2-INCH
|-n -| Install or Connect
1. Cam plate (16) to the cam side gear (21).
2. Wave spring.
3. Clutch plates.
• Alternate the plates as shown in figure 1.
4. Thrust sleeve (14).
• Press the thrust sleeve flush with the side gear
disc splines.
5. Guide clips (20) to the plates.
• Use grease in the clips to hold them in place
on the plates.
• If the side gear or thrust sleeve has been replaced,
measure and record the overall length of the gear
assembly from the front of the gear to the back of
the thrust sleeve (14) including the side gear washer
(13).
• Compare this reading with the reading obtained
earlier in this section.
• If the new reading is more than 0.003-inch higher or
lower than the original, select a thrust washer that
will return the reading closest to the original
reading.
-INCH
2
8 8 2
plates. V — 10 plates.
LOCKING DIFFERENTIALS 4B7-3
ADJUSTMENT OF THE DIFFERENTIAL
• If it is necessary to replace the cam gear, the right
side gear, or the thrust block, the entire differential
must be adjusted. The differential is adjusted by
using selective thickness thrust washers behind
each side gear, and a selective thickness thrust
block between the side gears.
• It is important to build up the differential properly, as
the proper clearances between parts is necessary
for the proper operation of the units.
• There are three adjustments to be made:
(1) Left side gear backlash.
(2) Right side gear backlash.
(3) Thrust block clearance.
Left Side Gear Backlash Adjustment
1. Install the cam unit and thrust washer (13) to the
flange end of the case.
2. Place the pinion gears (7) and thrust washers into
the differential.
• Align them with the pinion shaft hole.
3. Press down the side gear, and install the pinion
shaft (18) and lock screw (3).
• If the side gear cannot be pressed down far
enough to install the pinion shaft replace the
thrust washer with a thinner washer.
4. Rotate the pinion gear closest to the lock screw so
that one of the teeth is pointing downward
(perpindicular to the ring gear flange).
5. Insert a large tapered tool such as a screwdriver
firmly between the side gear and the pinion shaft.
6
. Mount a dial indicator to the ring gear flange, and
place the stem of the indicator on one of the teeth
on the pinion gear closest to the lock screw (figure
5).
7. Pull the pinion gear firmly into its seat, and rotate
the gear back and forth while reading the dial
indicator. Record the reading.
8
. Repeat steps 4 - 7 on the opposite pinion gear.
9. The backlash should be between 0.254 and 0.457
0.010
mm ( and 0.018-inch).
10. If the backlash is too high, use a thicker thrust
washer.