such parts as are necessary will eliminate costly and
is used, water is trapped in the cored passage of the
avoidable drive unit failure.
castings and in the close clearances between parts as
well as on the parts. This can lead to corrosion (rust) of
A. Inspect all bearings, cups and cones, including those
critical parts of the assembly and the possibility of
not removed from parts of the drive unit and replace
circulating rust particles in the lubricant. Premature
if rollers or cups are pitted or damaged in any way.
Remove parts needing replacement with a suitable
by this practice. Assembled drive units cannot be
puller or in a press with sleeves.
properly cleaned by steam cleaning, dipping or slushing.
Avoid the use of drifts and hammers. They may
Complete drive unit disassembly is a necessary
easily mutilate or distort component parts.
requisite to thorough cleaning.
B. Inspect first reduction bevel or hypoid and second
reduction spur gears for wear or damage. Gears
Rough parts such as differential carrier castings,
which are pitted, galled or worn or broken through
cast brackets may be cleaned in hot solution tanks with
case hardening should be replaced.
mild alkali solutions providing these parts are not ground
When necessary to replace the pinion or gear of a
or polished. The parts should remain in the tank long
gear set, the entire gear set should be replaced.
enough to be thoroughly cleaned and heated through.
We assume no responsibility for gears of these
types when replaced in any other manner.
parts should be thoroughly rinsed after cleaning to
C. Inspect the differential assembly for the following:
remove all traces of alkali.
1. Pitted, scored or worn thrust surfaces of
differential case halves, thrust washers,
spider trunnions and differential gears.
Exercise care to avoid skin rashes
Thrust washers must be replaced in sets.
and inhalation of vapors when using
The use of a combination of old and new
washers will result in premature failure.
2. Wear or damage to the differential pinion and
side gear teeth.
Completely assembled axles may be steam
cleaned on the outside only, to facilitate initial removal
Always replace differential pinions and side
and disassembly, providing all openings are closed.
gears in sets.
Breathers, vented shift units, and all other openings
should be tightly covered or closed to prevent the
D. Spur pinions for wear or damage to teeth.
possibility of water entering the assembly.
Check end of pinion for indications of brinelling
caused by worn splines. Replace the parts if the
Parts should be thoroughly dried immediately
splines of the pinion and/or thru-shaft are worn,
after cleaning. Use soft, clean, lintless absorbent paper
permitting movement of the pinion on the thru-
towels or wiping rags free of abrasive material, such as
lapping compound, metal filings or contaminated oil.
Bearings should never be dried by spinning with
F. Axle shafts for indications of torsional fractures and
runout. Axle shafts should be inspected between
centers to ascertain the amount of runout of the
ground surfaces. Runout at the shaft flange and
Parts that have been cleaned, dried, inspected
splines should not exceed .005" total indicator
and are to be immediately reassembled should be
coated with light oil to prevent corrosion. If these parts
are to be stored for any length of time, they should be
treated with a good RUST PREVENTIVE and wrapped
A. Replace all worn or damaged parts. Hex nuts with
in special paper or other material designed to prevent
rounded corners, all lock washers, oil seals and
gaskets should be replaced at the time of overhaul.
Use only genuine Rockwell-Standard parts for
It is impossible to overstress the importance of
satisfactory service. For example, using gaskets of
careful and thorough inspection of drive unit parts prior
foreign material generally leads to mechanical
Thorough visual inspection for
indications of wear or stress, and the replacement of