TM-9-2320-279-10-1
M977 SERIES, 8x8 HEAVY EXPANDED MOBILITY TACTICAL TRUCKS (HEMTT)
OPERATOR’S MANUAL VOLUME 1 OF 2
DECEMBER 1998
CHANGE 5
TM-9-2320-279-10-1 - Page 593 of 773
TM 9-2320-279-10- 1
Troubleshooting Index (Cont)
3-3. TROUBLESHOOTING SYMPTOMS (CONT).
Table 3-1. Symptom Inde x
Troubleshooting
Procedure
Page
AIR SYSTE M
Air horn will not operate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22
Buzzer sounds and AIR indicator is lit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
Loses pressure or AIR indicator lights and buzzer sounds during
operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Trailer brake does not apply when service brake treadle or parking
brake is used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Windshield washer will not operate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
ELECTRICAL SYSTE M
One or more lighting circuits not operating . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
ENGIN E
Cranks but fails to start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Excessive engine oil consumption. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Fails to crank when engine start switch is turned to start position. . . . . 3-4
Low OIL PRESS gage indication.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Overheats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Starts or runs roughly after proper warmup. Does not develop full
power or makes excessive exhaust smoke . . . . . . . . . . . . . . . . . . . . . . . 3-6
Will not stop running when ENGINE STOP switch is activated . . . . . . . . . 3-10
HYDRAULIC SYSTE M
One or more hydraulic circuits will not operate . . . . . . . . . . . . . . . . . . . . . 3-25
Operates either too slow, too fast, or with jerky movements . . . . . . . . . . 3-25
MATERIAL HANDLING CRANE (M977, M985)
Boom operation abnormal when telescoping in or out. . . . . . . . . . . . . . . . 3-28
Boom raises or lowers slowly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29
Boom will not raise or lower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30
Boom will not telescope in or out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31
Crane controls sticking in engaged position . . . . . . . . . . . . . . . . . . . . . . . . . 3-32
Crane will not operate or operates abnormally. . . . . . . . . . . . . . . . . . . . . . 3-33
Hoist operation slow or abnormal when lifting or lowering load. . . . . . . . 3-34
Hoist will not lift load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35
Mast raises or lowers abnormally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36
Mast raises or lowers slowly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36
Outrigger operation slow or abnormal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-37
Swing operation abnormal in both directions . . . . . . . . . . . . . . . . . . . . . . . 3-37
Swing operation abnormal in one direction only . . . . . . . . . . . . . . . . . . . . 3-38
3- 2
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