TM-9-2320-272-24-4
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 4 OF 4
JUNE 1998
TM-9-2320-272-24-4 - Page 374 of 836
TM 9-2320-272-24-4
5-55. REAR COVER AND LOW PLANETARY CARRIER MAINTENANCE (Contd)
c. Cleaning and Inspection
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
For general cleaning instructions, refer to para. 2-14.
For general cleaning instructions, refer to para. 2-15.
Inspect rear cover (1) for breaks and cracks. Replace rear cover (1) if broken or cracked.
Measure governor clearance in bore (2) of rear cover (1). Replace rear cover (1) if clearance exceeds
.0035 in. (.0089 mm).
Inspect governor support pin (9) for looseness, bends, and breaks. Replace governor support pin (9)
with pin remover if loose, bent, or broken.
Inspect low planetary carrier (5) for missing or twisted splines (6). Replace low planetary carrier (5)
if splines (6) are missing or twisted.
Inspect low planetary carrier (5) for burrs. If burrs are found, remove using crocus cloth.
Inspect roller bearing (7) on low planetary carrier (5) and race (8) in rear cover (1). Replace
bearing (7) and race (8) as a set if defective.
NOTE
Perform steps 9 and 10 only if bearing or race is defective.
Pin must be removed to remove bearing.
Remove pin (4) and roller bearing (7) from low planetary carrier (5). Discard pin (4).
Remove race (8) from rear cover (1) using bearing puller.
Measure thrust washer (3) thickness. Discard thrust washer (3) if thickness is less than 0.091 in.
(2.31mm).
Inspect thrust washer (3) for scoring. Discard if scored.
Inspect twenty-six piston return springs (10) for discoloration due to overheating. Discard piston
return springs (10) if discolored.
Inspect twenty-six piston return springs (10) for broken coils or coils distorted due to wear. Discard
piston return springs (10) if broken or distorted.
Inspect twenty-six piston return springs (10) for serviceability by checking load when compressed
with spring tester. Discard spring (10) if spring (10) does not give load according to table 5-15,
Spring Data.
Table 5-15. Spring Data.
SPRING
Piston return spring
COLOR
FREE LENGTH
COMPRESSED LENGTH
UNDER LOAD
Solid orange,
1.28 in.
0.95 in.
13.6-16.4 lb
yellow stripe
(32.5 mm)
(24.1 mm)
(60.5-72.9 N)
5-368
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