TM-9-2350-311-20-1
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR HULL, POWERPLANT, DRIVE CONTROLS, TRACKS, SUSPENSION, AND ASSOCIATED COMPONENTS
AUGUST 1994
TM-9-2350-311-20-1 - Page 75 of 1275
TM 9-2350-311-20-1
ITEM
NO.
7
8
INTERVAL
Semiannual
Semiannual
ITEM TO BE
INSPECTED
Engine Fan Drive
System
Fan Gear Case
PROCEDURE
Perform backlash test as follows:
a. Disconnect both battery ground cables.
b. Open air intake grille.
c. Mark any accessible blade (5).
d. While holding the opposite fan impeller, rotate
marked blade as far left as possible. Mark (6) fan
housing directly above blade mark.
e. While holding opposite fan impeller, rotate marked
blade as far right as possible. Mark (7) fan housing
directly above the blade mark.
f. Measure distance (8) between marks. If distance is
over 1 in. (2.5 cm), backlash is excessive. Notify support
maintenance.
g. Inspect fan for cracked and loose rubber boot and
loose retaining ring on boot covering the drive shaft U-
joints.
WARNIN G
Dry-cleaning solvent (P-D-680) is toxic and
flammable. Wear protective goggles and
gloves and use only in a well ventilated area.
Avoid contact with skin, eyes, and clothes, and
don’t breath vapors. Do not use near open
flame or excessive heat. The flashpoint for type
#1 is 100°F (38°C) and for type #2 is 138°F
(59°C). If you become dizzy while using dry-
cleaning solvent, get fresh air immediately and
get medical aid. If contact with eyes is made,
wash your eyes with water and get medical aid
immediately.
NOT FULLY
MISSION
CAPABLE IF:
f. Backlash is
over 1 in. (2.5
cm).
g. Cracked
rubber boot or
loose retaining
ring on covers
for drive shaft U-
joint.
2-27
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