TM-9-2320-280-20-2
TRUCK, UTILITY: M998 SERIES
TECHNICAL MANUAL; UNIT MAINTENANCE; VOLUME 2 OF 3
JANUARY 1996
TM-9-2320-280-20-2 - Page 112 of 951
3-49. MUFFLER AND CATALYTIC CONVERTER REPLACEMENT
(M1123 AND “A2” VEHICLES ONLY)
This task covers:
a. Removal
b. Installation
WARNING
Do not touch hot exhaust system components with bare hands.
Severe injury will result.
CAUTION
Support muffler and catalytic converter during replacement.
Failure to do so may result in damage to equipment.
1.
Remove two clamps (12) and heat shield (13) from crossover pipe (14).
2.
Remove four nuts (7) and U-bolt (25) from heat shield (11), support bracket (24), and muffler (26).
3.
Loosen clamp (8) and remove heat shield (11) from catalytic converter (18).
4.
Remove two nuts (10) and heat shield (4) from muffler (26).
5.
Remove three locknuts (16), washers (15), capscrews (23), and washers (15) from catalytic
converter (18) and crossover pipe (14). Discard locknuts (16).
6.
Remove two nuts (21), lockwashers (20), and U-bolt (17) from catalytic converter (18) and support
bracket (19). Discard lockwashers (20).
7.
Remove manifold seal assembly (22) by pulling catalytic converter (18) towards rear of vehicle.
Discard manifold seal assembly (22).
NOTE
It may be necessary to lower rear propeller shaft (para. 6-5) to
gain access to locknuts on muffler hanger.
8.
Remove four locknuts (2), washers (3), capscrews (27), washers (3), two retaining plates (28), and
muffler (26) from muffler hanger (1). Discard locknuts (2).
9.
Remove two locknuts (34), washers (31), capscrews (32), washers (31) insulator (29), retaining
plate (33), and bracket (30) from muffler (26). Discard locknuts (34).
1.
Install bracket (30), insulator (29) and retaining plate (33) on muffler (26) with two washers (31),
capscrews (32), washers (31), and locknuts (34). Tighten locknuts (34) to 10 lb-ft (14 N
•
m).
2.
Install muffler (26) and two retaining plates (28) on muffler hanger (1) with four washers (3),
capscrews (27), washers (3), and locknuts (2).
3.
Install catalytic converter (18) on bracket (19) with U-bolt (17), two lockwashers (20), and nuts (21).
b. Installation
a. Removal
INITIAL SETUP:
Applicable Models
M997A2, M1025A2, M1035A2, M1043A2,
M1045A2, M1097A2, M1123
Tools
General mechanic’s tool kit:
automotive (Appendix B, Item 1)
Materials/Parts
Nine locknuts (Appendix G, Item 128)
Manifold seal assembly (Appendix G, Item 197)
Two lockwashers (Appendix G, Item 167)
Manual References
TM 9-2320-280-24P
Equipment Condition
Tailpipe removed (para. 3-47).
General Safety Instructions
Do not touch hot exhaust system components with
bare hands.
TM 9-2320-280-20-2
3-90
Change 3
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