GMC 1990 Light Truck Repair Manual page 151

• 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
j y 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, brinelling 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
Inspect
L*
• Shims for cracks and chips. Damaged shims should
be replaced with an equally sized service shim.
ASSEMBLY OF THE REAR AXLE
Install or Connect
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).
8 2
V -INCH RING GEAR 4B2-5
Figure 9—Installing the Front Pinion Bearing Cup
PINION DEPTH ADJUSTMENT
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. Install 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.
Tighten
• Stud nut to 2.2 N m (20 in. lbs.).
Rotate the gage plate and bearings several
6
.
complete revolutions to seat the bearings.
Figure 10—Installing the Rear Pinion Bearing Cup