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 34 of 1258

TM 9-2320-280-34
Table 2-1.
Mechanical Troubleshooting (Cont'd
)
MALFUNCTION
TEST OR INSPECTION
20.
2-3 SHIFT SOFT OR SUPS
Step 1.
If oil pressure in 'D" (drive) at 1000 rpm is low, proceed to step 2. If oil pressure is normal,
proceed to step 4.
Step 2.
Perform steps 7 through 10 of malfunction 16.
Step 3.
Perform steps 4 through 9 of malfunction 17.
Step 4.
Perform steps 8 and 9 of malfunction 18.
Step 5.
Check front servo for broken or missing spring and leak at servo pin. Repair front servo
(chapter 17) if damaged.
Step 6.
Air check direct clutch piston for proper operation. If piston exhibits excessive leakage, proceed
to step 7. If operation is normal, proceed to step 8.
Step 7.
Check direct clutch piston, plates, and release springs for damage or incorrect assembly.
Repair intermediate clutch (para. 17-8) if damaged.
Step 8.
Check transmission case passages for leaks. Replace transmission (para. 7-6) if case is
damaged.
END OF TESTING!
21.
2-3 SHIFT FIRM OR ROUGH
Step 1.
If oil pressure in "D' (drive) at 1000 rpm is normal, proceed to step 2. If oil pressure is high,
proceed to step 5.
Step 2.
Check front accumulator for damaged piston, rings, and broken or missing spring; check valve
to accumulator feed for obstructions. Replace control valve (chapter 17) if damaged.
Step 3.
Air check direct clutch piston for leak to outer area of clutch piston; check center piston seal for
damage.
Repair direct clutch (para. 17-8) if damaged.
Step 4.
Check center support and second oil ring for damage. Repair center support (para. 17-9) if
damaged.
Step 5.
Perform steps 7 through 10 of malfunction 16.
Step 6.
Perform steps 7 through 10 of malfunction 18.
END OF TESTING!
22.
NO ENGINE BRAKING - SECOND GEAR
Step 1.
Check front servo piston for leaking oil rings and damaged piston. Replace damaged
components (chapter 17).
Step 2.
Check front accumulator piston for leaking oil rings and damaged piston. Replace control valve
(chapter 17) if damaged.
Step 3.
Check front band for damage and proper installation. Replace front band (chapter 17) if
damaged.
END OF TESTING!
23.
NO ENGINE BRAKING - FIRST GEAR
Step 1.
Check for missing or incorrectly installed check balls. Replace missing check balls (chapter
17).
Step 2.
Check transmission case for damage at check ball locations. Replace transmission (para. 7-6)
if damaged.
Step 3.
Check rear servo for leaking oil seal rings and damaged piston. Repair rear servo (para. 17-11)
if damaged.
Step 4.
Check rear band apply pin for proper length. Replace pin (chapter 17) if length is not correct.
Step 5.
Check rear band for damage and proper installation. Replace rear band (chapter 17) if
damaged.
END OF TESTING!
2-10


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