TM-9-2320-280-34 HMMWV Direct Support & General Support Maintenance Manual Download
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TM 9-2320-280-34 Table 2-1. Mechanical Troubleshooting (Cont’d) MALFUNCTION TEST OR INSPECTION 30. NO 1-2 UPSHIFT OR DELAYED UPSHIFT Step 1. If oil pressure in “D "(overdrive) at 1000 rpm is normal, proceed to step 2. If oil pressure is high, proceed / to step 3. Step 2. Check results of control valve and governor line pressure test (TM 9-2320-280-20). Step 3. If oil pressure in N" (neutral) at 1000 rpm was normal, proceed to st ep 4. If oil pressure was high, proceed to step 4. Step 4. Check control valve spacer plate for obstructions. Clean or replace spacer plate (chapter 17). END OF TESTING! 31. 1-2 SHIFTS SOFT OR SLIPS Step 1. Check transmission oil pressure response to varying throttle openings. Pressure should respond rapidly to quick changes in throttle opening. If oil pressure response is poor, proceed to step 2. If oil pressure response is normal, proceed to step 3. Step 2. If oil pressure in “ D “ (overdrive) at 1000 rpm is low, proceed to step 3. If oil pressure is normal, proceed to step 9. Step 3. Check oil pump for obstructed oil passages or damage. Repair oil pump (para. 17-29). Step 4. Check forward clutch seals for damage. Replace damaged seals (para. 17-22). Step 5. Check center support oil seal rings for damage. Replace damaged rings (para. 17-20). Step 6. Check rear servo piston and oil seal rings for damage. Repair rear servo (para. 17-27) if damaged. Step 7. Check front accumulator piston and oil seal rings for damage. Replace control valve (chapter 17) if accumulator piston components are damaged. Step 8. Check transmission case for internal damage or porosity. Replace transmission (para. 7-8) if case is damaged or porous. Step 9. Inspect control valve for nicks on machined surfaces or voids in casting, check 1-2 accumulator valve train for stuck valves or incorrect assembly; check front accumulator piston and oil seal rings for damage. Replace control valve (chapter 17) if any damage is fo und. Step 10 Check rear servo and rear accumulator pistons and oil seal rings for damage. Repair rear servo (para. 17-11) if damaged. Step 11. Check center support bolt for looseness. Tighten to 20-25 lb-ft (27-34 N-m). WARNING Compressed air used for cleaning purpose will not exceed 30 psi (207 kPa). Use only with effective chip guarding and personnel protective equipment (goggles, shield, gloves, etc.). Step 12. Air check intermediate clutch piston for proper operation. If operation is normal, p roceed to step 13. If piston exhibits excessive leakage, proceed to step 14. Step 13. Check intermediate clutch piston, plates, and release springs for damage or incorrect assembly. Repair intermediate clutch piston (para. 17-25) if damaged. Step 14. Check center support for missing orifice plug. Replace transmission (para. 7-8) if plug is missing. END OF TESTING! 2-14