PAR 71-72
PRELIMINARY INSTRUCTIONS FOR
CHAP 5, SEC I
POWER TRAIN OVERHAUL
WARNING
Dry Cleaning Solvent P-D-680 is toxic
and flammable. To avoid injury, wear
protective goggles and gloves and use
in a well-ventilated area. Avoid con-
tact with skin, eyes, and clothes, and
d o n o t b r e a t h e v a p o r s . D o n o t u se
near open fire or excessive heat. The
flash point for Type I dry cleaning
solvent is 100°F (38°C), and for Type
II is 138°F (50°C). If you become dizzy
while using dry cleaning solvent, get
fresh air immediately and get medical
a i d . I f c o n t a c t w i t h e y e s i s m a d e,
wash your eyes with water and get
medical air immediately.
( 1 ) E v e r y c o m p o n e n t s h o u l d be
thoroughly cleaned after the transmission
is disassembled. Cleaning is necessary to
ensure effective inspection for wear, dam-
age and serviceability of components.
( 2 ) A b r a s i v e s , f i l e s , s c r a p e r s,
wire brushes and sharp tools should never
be used on surfaces where finish is impor-
tant to the operation or sealing of parts,
except where specifically recommended.
(3) Gum or varnish deposits may
b e r e m o v e d b y s o a k i n g i n d r y c l e a n i ng
solvent or mineral spirits and using a
s o f t - b r i s t l e b r u s h . C r o c u s c l o t h m a y be
used to remove minor surface irregulari-
ties. Lapping compound may be used, if
required, in valve body bores to prevent
valves from sticking. Clean thoroughly to
remove compound after use.
(4) A soft wire (brass or copper)
may be used to clean oil passages. Always
flush such passages thoroughly after clean-
ing.
(5) If steam cleaning is used, dry
the cleaned parts immediately with com-
pressed air and apply a film of oil to pre-
vent rusting. Never use lye or caustics
which will corrode or etch metal surfaces.
( 6 ) D o n o t c l e a n t h e l u b r i c a nt
from new bearings.
K e e p n e w b e a r i n gs
wrapped until they are to be installed.
Soak bearings which have been in service
in dry cleaning solvent or mineral spirits
to loosen deposits of dirt. Do not spin the
bearings during cleaning or drying. After
cleaning, turn the bearings by hand and
note any evidence of grit. Reclean them
if grit is present.
Refer to TM 9-214 for
further information on cleaning bearings.
72. INSPECTION AND REPAIR
RECOMMENDATIONS
N o t e . Just before or during assem-
b l y , l u b r i c a t e a l l s e a l s , s h a f t s,
gears, bearings, valves, and other
m o v i n g p a r t s w i t h t r a n s m i s s i o n
oil. This lubrication will protect
the parts during storage and at
initial start-up.
a. Castings, Forgings, Machined
—
Surfaces
(1) Inspect all castings and forg-
ings for breaks, cracks and wear or scoring
that would impair serviceability. Remove
nicks and small surface irregularities with
crocus cloth or a soft stone.
( 2 ) I n s p e c t a l l o i l p a s s a g e s f or
obstructions and dirt. Reclean passages if
necessary.
( 3 ) I n s p e c t m o u n t i n g f a c e s f or
nicks, scratches and scores. Remove minor
defects with crocus cloth or a soft honing
stone. Replace any parts in which defects
that cannot be corrected will impair the
operation of the transmission.
(4) Inspect threaded openings for
damaged threads. Chase damaged threads
with the correct size used tap.
Note. A new tap will cut oversize.
If threads are stripped, discard the
part unless it can be satisfactorily
repaired by installing an insert.
( 5 ) R e p l a c e h o u s i n g s o r o t h e r
cast parts that are cracked or broken.
b . Roller or Ball Bearings. Refer to
TM 9-214 for proper cleaning and inspec-
tion procedures.
c . N e e d l e - t y p e R o l l e r B e a r i n g s . I n-
spect the bearings for free and smooth
rotation, broken or missing rollers, and
Change 2 75
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