Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
for models with 8-1/2 or 8-7/8 inch ring gear, Figs. 16 and 17, or suitable equivalents. On models with 8-7/8 inch ring gear, substitute cloverleaf
gauge plate J-21777-36 for plate J-21777-29. Follow all tool manufacturer's recommendations when installing gauge assembly.
a. Assemble gauge plate onto preload stud.
b. Hold pinion bearings in position, insert stud through rear bearing and pilot and front bearing and pilot, then install retaining nut and tighten
nut until snug.
c. Rotate tool to ensure that bearings are properly seated.
d. Hold preload stud and tighten nut until 20 inch lbs. torque are required to rotate stud.
Tighten nut in small increments, checking rotating
torque after each adjustment, to prevent damaging bearings.
e. Mount side bearing discs on arbor, using step for disc that corresponds to base of housing.
f.
Mount arbor and plunger assembly in housing, ensuring that side bearing discs are properly seated, install bearing caps and tighten cap bolts
to prevent bearing discs from moving.
4.
Mount suitable dial indicator on arbor stud with indicator contact button bearing against top of arbor plunger.
5.
Preload indicator 1/2 revolution and secure to arbor mounting stud in this position.
6.
Place arbor plunger on gauge plate, rotating plate as needed so that plunger rests directly on button corresponding to ring gear size.
7.
Slowly rock plunger rod back and forth across button while observing dial indicator.
8.
At point on button where indicator registers greatest deflection, zero dial indicator.
Perform steps 7 and 8 several times to ensure correct
setting.
9.
Once verified zero reading is obtained, swing plunger aside until it is clear of gauge plate button and record dial indicator reading.
Indicator will
now read required pinion depth shim thickness for a ``nominal'' pinion.
10.
Inspect rear face of drive pinion to be installed for a pinion code number. This number indicates in thousandths of an inch necessary modification
of pinion shim thickness obtained in step 9.
11.
Select pinion depth adjusting shim as follows:
a. If pinion is stamped with a plus (+) number, add that number of thousandths to dimension obtained in step 9.
b. If pinion is stamped with a minus ( - ) number, subtract that many thousandths from dimension obtained in step 9.
c. If pinion is not stamped with plus or minus number, dimension obtained in step 9 is correct shim thickness.
12.
Remove gauging tools and pinion bearings from housing, noting installation position of bearings.
PINION INSTALLATION
1.
Install selected shim onto pinion shaft, lubricate rear pinion bearing with specified axle lubricant, then press rear bearing onto pinion using suitable
spacers.
2.
Install new collapsible spacer onto pinion shaft, then insert pinion assembly into housing.
3.
Lubricate front pinion bearing, install bearing into housing and tap bearing over pinion shaft with suitable drift while assistant holds pinion in
place.
Old pinion nut and suitable large washer can be used to seat front bearing on pinion, but care must be taken not to collapse spacer
if this method is used.
4.
Install new pinion seal in housing, coat seal lips with grease, then mount driveshaft yoke on pinion shaft, lightly tapping yoke until several pinion
shaft threads protrude from yoke.
5.
Coat rear of pinion washer with suitable sealer, then install washer and new pinion nut.
6.
Hold drive shaft yoke with suitable tool, then alternately tighten pinion nut and rotate pinion until endplay is reduced to zero.
7.
When endplay is reduced to zero, check pinion bearing preload using suitable torque wrench.
8.
Continue tightening pinion nut in small increments until specified pinion bearing preload is obtained, rotating pinion and checking preload after
each adjustment.
Exceeding preload specification will compress collapsible spacer too far, requiring replacement of spacer. If preload
specification is exceeded, spacer must be replaced and adjustment procedure must be repeated. Do not loosen pinion nut to reduce
preload.
9 1/2 Inch Ring Gear
