GMC 1989 Light Duty Truck Repair Manual page 194

4B5-6 DANA REAR AXLES
AXLE HOUSING
L 9
Inspect
• The ca rrier bore for nicks or burrs that w ould
prevent the outer diameter of the pinion seal from
sealing. Remove any burrs that are found.
• The bearing cup bores for nicks or burrs. Remove
any burrs that are found.
• The housing for cracks. Replace the housing if any
cracks are found.
• The housing for foreign material such as metal
chips, dirt, or rust. Refer to " C leaning" in this
section.
DIFFERENTIAL
Inspect
I
9
• Pinion gear shaft for unusual wear.
• Pinion gear and side gear teeth for wear, cracks,
scoring, and spalling.
• Thrust washers for wear.
• The fit of the differential side gears in the differential
case.
• 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
1?
• 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 w hich 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
Inspect
I9
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.
B earing 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.