TM-9-2320-272-24-2
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 2 OF 4
JUNE 1998
TM-9-2320-272-24-2 - Page 692 of 991
TM 9-2320-272-24-2
Table 4-1. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
30. LOW MAIN OPERATING PRESSURE AT ALL SHIFT RANGES
Perform transmission pressure test (para. 5-60).
If oil pressure is still low, replace transmission (para. 4-71).
END OF TESTING!
31. CLUTCH SLIPPAGE IN ALL FORWARD AND/OR REVERSE GEARS
Replace transmission (para. 4-71).
END OF TESTING!
32. EXCESSIVE VEHICLE CREEP (FIRST AND REVERSE)
Check and adjust engine idle (para. 3-42 or 3-43).
END OF TESTING!
33. VEHICLE MOVES IN NEUTRAL
Check shift range selector (para. 4-73).
a.
Adjust shift selector linkage (para. 4-75).
b.
If malfunction continues, replace transmission (para. 4-71).
END OF TESTING!
34. NO RESPONSE TO SHIFT LEVER MOVEMENT
Check if shift linkage is disconnected or broken.
a.
Connect or replace linkage if necessary (para. 4-75).
b.
If linkage is sound, replace transmission (para. 4-71).
END OF TESTING!
35. OIL THROWN OUT OF OIL FILLER TUBE
Step 1. Check transmission oil level (table 2-1).
Drain or fill to proper level.
Step 2. Check and clean breather vent.
If worn or damaged, replace breather vent (para. 3-136).
Step 3. Disconnect vent line at breather, start engine, and check for compressed air coming through
vent line.
If air is present, perform compressed air and brake troubleshooting (para. 2-23).
Step 4. Replace transmission (para. 4-71).
END OF TESTING!
36. OIL LEAKING INTO CONVERTER HOUSING
Step 1. Check if leaking engine oil.
If leaking engine oil, replace engine rear crankshaft seal (para. 4-17 or 4-45).
Step 2. Check if leaking transmission fluid.
If leaking transmission fluid, replace transmission (para. 4-71).
END OF TESTING!
4-10
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