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TM 9-2520-246-34
distorted or damaged.
inspected to determine serviceability. Some wear or
damage will be visually evident; however, it may be
(6) Expansion Plugs. Replace all expansion
necessary to use tools or gages to, determine the extent
plugs.
of wear. The inspection procedure has two objectives:
the first is to eliminate any part or parts that are
(7) Retaining Nuts. Replace retaining nuts that
unsuitable for use or doubtful parts that could
have damaged threads, cuts, or cracks.
conceivably cause the premature failure of the rebuilt
unit; the second, and equally important, is to reduce
scrapping of parts that retain a high percentage of
(8) Gearshafts. Inspect gearshafts for gall marks
or flat spots. Check gearshafts for fit as outlined in
useful life. Because the decision whether a part should
para b(1) above. Check bearing-to-shaft fit. Refer to
be scrapped or reused is frequently a matter of
repair and rebuild standards. Smooth any minor
judgment, this operation should be performed by
imperfections with crocus cloth or honing stone.
personnel experienced in the maintenance of
Reject for any other damage. Shafts that are scored or
transmissions, transfers, and power takeoffs.
pitted must be replaced.
(3) Instructions for the removal of minor
{9) Gears. The experience and good judgment of
imperfections and defects are included in this section
the inspector are required to a greater degree in
because they facilitate the inspection procedure. Every
judging gears than in any other operation. It is not
part which requires it must be washed, rinsed, and
possible to give arbitrary instructions as to when a
dried upon completion of the repair.
particular condition makes a gear unfit for further
use. The major and minor defects can only be pointed
b. Inspection Procedure.
out, leaving the in-between scrap or salvage decision
to the discretion of the individual.
(1) Casting. Inspect all gasket surfaces, all
bearing caps and shifter shaft covers. Remove any
(a) Small nicks or burs on the engaging ends of
burs, scratches, or gouges from these surfaces with a
the teeth may be removed with a small honing stone.
hand-honing stone. Clean all burs or foreign material
This is only practical for minor defects. Fractures of
from snapring grooves and expansion plug grooves.
the teeth are cause for rejection.
Check the cases for cracks or small pin holes, paying
particular attention to areas that were marked for
(b) Teeth which are fractured or burred must be
attention prior to initial cleaning. Cracks that do not
examined very carefully. Small burs may be removed
extend into bearing bores or mounting holes may be
by honing. Fractured areas, provided there are no
repaired. Refer to TM 9-237 for procedures for
hairline cracks radiating away from the area, may also
welding or brazing cast iron. Check and clean all
be smoothed by honing.
tapped holes. Mark any damaged holes or damaged or
broken studs for repair. Try the gearshafts in the shaft
(c) Fractures due to metal fatigue are cause for
bores of the cases. The shafts should be a snug fit in
rejection.
both the front and rear bore. If there is loose fit in
(d) When the hubs of gears are scored, gouged,
any bore, try a new, unused shaft in the bore. Discard
or burred seriously, the gears must be discarded.
either the case or the old gearshaft, whichever is found
Minor imperfections may be smoothed out by honing.
to cause looseness.
Excessive wear will be revealed when end play is
(2) Clutch Housing. Inspect the clutch housing
checked during the subsequent assembly operations.
for breaks or cracks. Small cracks that do not extend
(e) Examine the internal splines of all sliding
into the mounting holes may be repaired by welding.
gears. Twisted or broken splines are cause for
(3) Bearing Caps. Press the oil seal from the
rejection. Remove minor defects by honing. The
main shaft rear bearing cap, and discard the seal.
inspection of splines is discussed in para (10) below.
Inspect all bearing caps for burs, gouges, or scratches
on the gasket surface, and smooth out with hand-
(10) Mainshafts and Output Shafts. Inspect
bearing journals; reject for obvious defects such as
honing stone if necessary.
scored or galled spots or wear beyond limits specified
(4) Gear Spacers and Thrust Washers. Replace
in the repair and replacement standards contained in
the respective chapter for each assembly. Inspect
all main shaft gear spacers, bearing spacers, and thrust
washers.
threads on output end of shaft. Clean any flattened
threads with a three-cornered file and wrap the
(5) Snaprings. Replace all snaprings. Snaprings
threads with three or four turns of friction tape as a
furnished as part of ball bearings may be reused if not
protective measure against further damage until the
2-16

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