Cleaning And Inspection; Cleaning; Inspection - GMC 1990 Light Truck Repair Manual

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 suitable 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 compressed air.

INSPECTION

It is very important to carefully and thoroughly inspect
all drive unit parts before assembly.
Thorough inspection of the drive parts for wear or
stress and subsequent replacement of worn parts will
eliminate costly drive component repair after reassembly.
AXLE HOUSING
L*
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" in this section.
DIFFERENTIAL
Inspect
L*
• Pinion gear shaft for unusual wear.
• Pinion gear and side gear teeth for wear, cracks,
scorring, spalling.
• Thrust washers for wear.
• The fit of the differential side gears in the differential
case.
• Fit of the side gear on the axle shafts.
• Differential case for cracks and scorring.
• Replace all worn parts.
PINION AND RING GEAR
Inspect
Pinion and ring gear teeth for cracking, chipping,
scorring, or excessive wear.
Pinion splines for wear.
Pinion flanges splines for wear.
Fit of the pinion on the pinion flange.
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.

CLEANING AND INSPECTION

T TRUCK FRONT AXLE 4C3-7
BEARINGS
Inspect
L*
• 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 front 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.
THRUST WASHERS, SHIMS AND
ADJUSTER SLEEVES
Inspect
L*
Shims and thrust washers for cracks and chips.
Damaged shims should be replaced with an equally
sized service shim.
Adjuster sleeves for damaged threads. Replace if
required.
SHIFT MECHANISM
Inspect (Figures 1 and 2)
Carrier connector (9) 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 damaged
splines and teeth. Replace if necessary.
Spring (16) for breakage.