GMC 1989 Light Duty Truck Repair Manual page 153

• The fit of the side gears on the axle shafts.
• Differential case for cracks and scoring.
• Replace all worn parts.
PINION AND RING GEAR
Inspect
• Pinion and ring gear teeth for cracking, chipping,
scoring, or excessive wear.
• Pinion splines for wear.
• Pinion flange splines for wear.
• The fit of the pinion on the pinion flange.
• The sealing surface of the pinion flange for nicks,
burrs, or rough tool marks which would cause
damage to the seals' inside diameter and result in
an oil leak.
• Replace all worn or broken parts.
• Ring and pinion gears are matched sets and are
both replaced any time a replacement of either is
necessary.
BEARINGS
L 1
Inspect
• Bearings visually and by feel.
• The bearings should feel smooth when oiled and
rotated while applying as much hand pressure as
possible.
• The large end of the bearing rollers for wear. This is
where tapered roller bearing wear is most evident.
• Bearing cups for wear, cracks, b rin e llin g and
scoring.
• Bearings and cups are only replaced as sets.
• If the rear axle was operated for an extended period
of time with very loose bearings, the ring gear and
drive pinion will also require replacement.
• Low mileage bearings may have minute scratches
and pits on the rollers and the bearing cups from the
initial preload. Do not replace a bearing for this
reason.
• Bearing caps for cracks or chips.
SHIMS
L 1
Inspect
• Shims for cracks and chips. Damaged shims should
be replaced with an equally sized service shim.
ASSEMBLY OF THE REAR AXLE
-►4- Install or C onnect
Tools Required:
J 8608 Rear Pinion Bearing Cup Installer
J 8611-01 Front Pinion Bearing Cup Installer
J 8092 Driver Handle
1. Front pinion bearing cup (39) using J 8611-01 and
J 8092 (figure 9).
2. Rear pinion bearing cup (5) using J 8608 and
J 8092 (figure 10).
81/2-INCH RING GEAR 4B2-5
Figure 9— Installing the Front Pinion Bearing Cup
PINION DEPTH ADJUSTM ENT
Tools Required:
J 8001 Dial Indicator Gage Set
J 21777-1 Arbor
J 21777-29 Gage Plate
J 21777-35 Rear Pilot Washer
J 21777-42 Front Pilot Washer
J 21777-43 Stud Assembly — Bolt
J 21777-45 Side Bearing Disc
1. Clean all the gage parts.
2 Lubricate the front and rear pinion bearings with
.
axle lubricant.
3. Place the bearings (39) and (5) into the pinion
bearing cups.
4. In s ta ll J 21777-35, J 21777-42, J 21777-29 and
J 21777-43 to the pinion bore (figure 11).
5. Hold the stud stationary at the flats of the stud.
T ighten
• Stud nut to 2.2 N-m (20 in. lbs.).
R otate th e gage p la te and b e a rin g s se ve ra l
complete revolutions to seat the bearings.
Figure 10 — Installing th e R ear Pinion B earing Cup