TM-9-2320-280-34

TRUCK, UTILITY: M998 SERIES

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE

JANUARY 1996
TM-9-2320-280-34

  TM-9-2320-280-34 - Page 29 of 1258

TM 9-2320-280-34
Change 1
2 - 5
MALFUNCTION
TEST OR INSPECTION
Table 2-1. Mechanical Troubleshooting (Cont'd)
4.
ENGINE KNOCKS (MECHANICAL NOISE)
Step 1.
Remove converter housing cover (TM 9-2320-280-20) and tighten torque converter capscrews to
32 lb-ft (43 N
•
m).
Step 2.
Remove and test fuel injection nozzles (para. 4-3). Replace defective fuel injection nozzles.
Step 2.1. Check for defective fuel injection pump (TM 9-2815-237-34). Replace defective fuel injection pump (para. 4-6).
Step 3.
Check for worn or damaged connecting rod bearings. Replace worn or damaged connecting rod bearings
(TM 9-2815-237-34).
Step 4.
Check for worn or damaged main bearings. Replace worn or damaged main bearings (TM 9-2815-
237-34).
Step 5.
Check for worn or damaged crankshaft. Replace worn or damaged crankshaft (TM 9-2815-237-34).
Step 6.
Check for worn or damaged pistons and connecting rods. Replace worn or damaged pistons and connecting
rods (TM 9-2815-237-34).
END OF TESTING!
5.
EXCESSIVE OIL LOSS OR CONSUMPTION
Step 1.
Check for oil leaks around oil pan, rocker arm covers, and timing gear cover oil seal. If any leakage is found,
repair as necessary (chapter 3).
Step 2.
Check for defective valve seals. Replace defective valve seals (TM 9-2815-237-34).
Step 3.
Check for worn valve guides. Repair worn valve guides (TM 9-2815-237-34).
Step 4.
Check for worn or damaged piston rings. Replace worn or damaged piston rings (TM 9-2815-237-34).
END OF TESTING!
6.
LOW OIL PRESSURE
Step 1.
Check for defective oil pump. Replace defective oil pump (para. 3-16).
Step 2.
Check for worn or damaged rod bearings. Replace worn or damaged rod bearings (TM 9-2815-237-34).
Step 3.
Check for worn or damaged main bearings. Replace worn or damaged main bearings (TM 9-2815-
237-34).
Step 4.
Check for worn or damaged crankshaft. Replace worn or damaged crankshaft (TM 9-2815-237-34).
END OF TESTING!
7.
EXCESSIVE ENGINE VIBRATION
Step 1.
Check for air in fuel lines. Bleed air from fuel lines (TM 9-2320-280-20).
Step 2.
Remove and test fuel injection nozzles (para. 4-3). Replace defective fuel injection nozzles.
Step 2.1. Check for defective fuel injection pump (TM 9-2815-237-34). Replace defective fuel injection pump (para. 4-6).
Step 3.
Check for broken engine mounts. Replace broken engine mounts (para. 3-3).
Step 4.
Remove converter housing cover (TM 9-2320-280-20) and tighten torque converter capscrews to
32 lb-ft (43 N
•
m).
Step 5.
Check for loose or damaged torsional damper. Replace if damaged (para. 3-7).
Step 6.
Check for damaged flywheel and missing counterweight on flywheel. Replace flywheel (TM 9-2815-237-34) if
damaged or counterweight is missing.
END OF TESTING!


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