Pinion Depth Adjustment; Pinion Installation; Differential Case Assembly - GMC 1989 Light Duty Truck Repair Manual

39. Bearing Cup
Figure 21 — Installing the Inner Pinion Bearing Cup

PINION DEPTH ADJUSTMENT

Tools Required:
J 36601 Pinion Depth Setting Gage
J 29763 Dial Indicator
1. Refer to figures 1 through 4 and 22.
2. Pinion depth is adjusted by selecting a shim (38) of
the proper thickness.
3. Lubricate the pinion bearings liberally with axle
lubricant.
4. A sse m ble J 29763 to the p ro pe r g a g in g arm
(J 36601-4 for K15-25 models, J 36601-3 for K35
models).
5. Install the pinion bearings and hold them in place.
6 . Insert the threaded rod of J 36601 through the
pinion bearings.
7. Install the proper pilot, flat washer, and nut.
8 . Tighten the nut while holding the threaded rod with
a wrench to adjust bearing preload. Adjust the nut to
obtain a preload of 1.0-1
M easure using an inch pound torque w rench.
Rotate the shaft several times to make sure the
bearings have seated, then measure again.
9. Push the dial indicator downward until the needle
rotates about three turns.
10. Tighten the dial indicator in this position.
11. Set the button of J 36601 on the differential bearing
22
bore (figure ).
12. Rotate the tool slowly back and forth until the dial
indicator reads the lowest point of the bore. Set the
dial indicator to ZERO. Repeat the rocking action of
the tool to verify the ZERO setting.
13. After the ZERO setting is obtained and verified,
grasp the gaging arm by the flats and move the tool
button out of the differential side bearing bore
(figure 22). Record the dial indicator reading.
14. The dial indicator reading is equal to the required
shim size. Example: If the dial indicator reads 0.508
mm in step 8 , a 0.508 shim is required. Available
shim sizes are listed in " Specifications."
15. Remove the tool and bearing cones.
J 3 65 9 8-3 (K 1 5 -2 5 )
/
F-5868
.6
N m (10-15 in. lbs.).
K TRUCK FRONT AXLE 4C4-11

PINION INSTALLATION

Install or C onnect (Figures 1 through 4 and 11,
23 and 24)
Tools Required:
J 35512 Bearing Installer (K15-25 Models)
J 36614 Bearing Installer (K35 Models)
J 8614-01 Pinion Flange Remover
J 36333 Seal Installer
1. Shim (38) to the pinion gear (37).
• The shim must be of the proper size, as
selected previously.
2. Bearing (39) onto the pinion gear using J 35512
(K15-25 models) or J 36614 (K35 models) (figure 23).
3. New spacer (40) onto the pinion gear.
4. Bearing (41) into the case.
5. Seal (42) into the case using J 36366 (figure 24).
6
. Pinion gear, with bearing and spacer, to the case.
7. Deflector (43), flange (44), washer (45) and nut (46).
• Apply PST Sealant (GM part no. 1052080 or
equivalent) to the pinion gear threads and on
both sides of the washer.
• Tighten nut (46) until no end play is detectable
while holding the flange (44) with J 8614-01
11
(figure ).
• No further tightening should be attempted until
the bearing preload has been checked.
€
M easure (Figure 25)
Pinion bearing preload. Use an inch pound torque
wrench (figure 25). The correct preload is 1.7-2.8
N m (15-25 in. lbs.).
1. Rotate the pinion with the torque wrench and
observe the reading.
2. If the preload torque is below specifications,
continue torquing the pinion nut in sm all
increm ents. Check the preload after each
tightening. Each tig hte nin g increases the
bearing preload by several inch pounds. If the
bearing preload is exceeded, the pinion will
have to be removed, and a new collapsible
spacer installed.
3. Once the preload has been obtained, rotate
the pinion several times to make sure that the
bearings have seated. Recheck the preload,
and adjust if necessary.

DIFFERENTIAL CASE ASSEMBLY

*n - Install or C onnect (Figures 1 through 4, and
26)
Tools Required:
J 22761 S id e B e a rin g
Models)
J 29710 Side Bearing Installer (K35 Models)
J 8092 Driver Handle
1. Side gear spacer (57) (K-35 m odels only), thrust
washers (53), and side gears (54) into the differential
case (35).
• Install the side gear spacer on the left-hand
shaft. K15-25 models do not have a spacer.
• If the same gears and washers are being used,
In s ta lle r (K 15-25