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 693 of 991
TM 9-2320-272-24-2
Table 4-1. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
37. ROUGH SHIFTING
Step 1. Check manual selector for proper operation.
If defective, replace manual selector (para. 4-73).
Step 2. Check shift cable for binding and proper adjustment.
Replace or adjust shift cable as necessary (para. 4-75).
Step 3. Check if modulator is sticking.
Replace modulator if necessary (para. 3-145).
Step 4. Check if modulator cable is kinked or out of adjustment.
Replace or adjust modulator cable as necessary (para. 3-145).
END OF TESTING!
38. TRANSMISSION OIL DIRTY, FOAMY, AND/OR MILKY
NOTE
Dirt/grit in transmission oil indicates oil needs to be changed
(step 1). Foaminess indicates contamination by air (step 2) or
water (step 3). Milkiness indicates contamination by water
(step 3).
Step 1. Check for dirt/grit.
a.
Perform transmission service procedure (para. 3-133).
b.
Inspect all external transmission fittings for looseness. If loose, tighten.
c.
Replace transmission (para. 4-71).
Step 2. Check for excessive foaming.
Ensure transmission fluid is at proper level (TM 9-2320-272-10). Drain or fill fluid as
necessary (LO 9-2320-272-12).
Step 3. Check for coolant in transmission fluid.
If coolant is present in transmission oil, replace transmission oil cooler (para. 3-140 or 3-141).
END OF TESTING!
39. OIL LEAK AT OUTPUT SHAFT
Check oil seal at output shaft flange for wear or damage.
If worn or damaged, replace seal and output flange (para. 4-78).
TRANSFER CASE
40. TRANSFER CASE WILL NOT SHIFT INTO GEAR
Step 1. Check shift linkage for proper adjustment.
Adjust shift linkage if necessary (para. 4-88).
Step 2. Check shift linkage for bends, breaks, or disconnections.
Repair or replace shift linkage (para. 4-88).
Step 3. If malfunction continues, replace transfer case (para. 4-94 or 4-95).
END OF TESTING!
4-11
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