Cleaning And Inspection; Cleaning; Inspection - Chevrolet 1991 Light Duty Truck Repair Manual

39. Differential pinion gears (56) and side gears (54).
• Roll the pinion gears out of the case with the
pinion thrust washers (55).
• Remove the side gears and the side gear

CLEANING

• Do not steam clean drive parts having ground and
polished surfaces such as gears, bearings, and
shafts. These parts should be cleaned in a suit­
able solvent. All parts should be disassembled
before cleaning.
• Parts should be thoroughly dried immediately after
cleaning. Use soft, clean, lintless rags. Parts may
be dried with compressed air. Do not allow the
bearings to spin while drying them with com­
pressed air.

INSPECTION

It is very important to carefully and thoroughly
inspect all drive unit parts before assembly.
Thorough inspection of the parts for wear or stress
and replacement of worn parts will help prevent costly
drive component repair after reassembly.
AXLE HOUSING
Inspect
• Carrier bore for nicks or burrs that would prevent
the outer diameter of the pinion seal from sealing.
Remove any burrs that are found.
• Bearing cup surfaces for nicks or burrs. Remove
any burrs that are found.
• Housing for cracks. Replace the housing if any
cracks are found.
• Housing for foreign material such as metal chips,
dirt, or rust. Refer to " Cleaning" .
DIFFERENTIAL
Inspect
• Pinion gear shaft for unusual wear.
• Pinion gear and side gear teeth for wear, cracks,
scoring, and spalling.
• Thrust washers for wear.
• Fit of the differencial side gears in the differential
case.
• Fit of the side gears on the axle shafts.
• Differential case for cracks and scoring.
PINION AND RING GEAR
Inspect
Pinion and ring gear teeth for cracking, chipping,
scoring, or excessive wear.
Pinion gear splines for wear.
8 1/4 AND 9 1/4-INCH RING GEAR 4C4-3

CLEANING AND INSPECTION

thrust washers (53). Mark the gears and
differential case as left and right.
• Remove spacer (57) (K3 models only).
40. Vent plug (60). Use a 6-point deep socket.
41. Bushings (48). Use J 36616 (figure 18).
Pinion flange splines for wear.
Fit of the pinion flange on the pinion gear.
Sealing surface of the pinion flange for nicks,
burrs, or rough tool marks which would cause
damage to the inside diameter of the pinion seal
and result in an oil leak.
Replace all worn or broken parts.
Ring and pinion gears are matched sets and must
both be replaced any time a replacement of either
is necessary.
BEARINGS
Inspect
I *
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 evi­
dent.
Bearing cups for wear, cracks, brinelling and scor­
ing.
Bearings and cups are only replaced as sets.
If the 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 very small
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, THRUST WASHERS AND ADJUSTER
SLEEVES
Inspect
• Shims and thrust washers for cracks and chips.
Damaged shims should be replaced with an equal­
ly sized service shim.
• Adjuster sleeves for damaged threads. Replace if
required.
SHIFT MECHANISM
Inspect
Carrier connector (9) (if used) for damaged splines
and teeth. Replace as required.
Shift fork (17) for wear, scoring, and damage to
thrust surfaces. Replace if needed.
Sleeve (22) and inner output shaft (23) for dam­
aged splines and teeth. Replace if necessary.
the