TM-9-2320-272-24-4
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 4 OF 4
JUNE 1998
TM-9-2320-272-24-4 - Page 364 of 836
TM 9-2320-272-24-4
5-53. FIRST CLUTCH MAINTENANCE
THIS TASK COVERS:
a. Removal
b. Cleaning and Inspection
c. Installation
d. Establishing Clearance
INITIAL SETUP:
APPLICABLE MODELS
All
SPECIAL TOOLS
First clutch clearance gauge (Appendix E,
Item 45)
TOOLS
General mechanic’s tool kit (Appendix E, Item 1)
Outside micrometer (Appendix E, Item 80)
Vernier caliper (Appendix E, Item 159)
Snapring pliers (Appendix C, Item 125)
REFERENCES (TM)
TM 9-2320-272-24P
EQUIPMENT CONDITION
Second clutch removed (para. 5-52).
SPECIAL ENVIRONMENTAL CONDITIONS
Work area clean and free from blowing dirt and
dust.
CAUTION
First clutch consists of a backplate, six clutch plates, and six clutch
discs. Keep all clutch parts together. Intermixing first clutch parts
with any other clutch pack will cause transmission damage.
a.
Removal
NOTE
Tag all first clutch parts for reassembly.
Backplate, five clutch discs, four clutch plates, and
rear planetary ring gear are removed as one unit.
1.
Remove snapring (5), backplate (6), five clutch discs (3), four clutch plates (2), and rear planetary
ring gear (1) from transmission housing (4).
2.
Remove remaining two clutch plates (2) and clutch disc (3) from transmission housing (4).
b. Cleaning and Inspection
1.
For general cleaning instructions, refer to para. 2-14.
2.
For general inspection instructions, refer to para. 2-15.
3.
Inspect clutch discs (3) for burned surfaces. If surfaces are burned, discard clutch discs (3).
4.
Inspect clutch plate (2) for burned surfaces. If surfaces are burned, discard clutch plate (2).
NOTE
Cast iron backplates marked number 1, 2, and 3 must have same
thickness as corresponding new malleable iron backplates 4,5, and 6.
5.
Measure backplate (6) thickness.
a. If thickness of backplate (6) marked No. 4 is less than 0.702 in. (17.83 mm), discard backplate (6).
b. If thickness of backplate (6) marked No. 5 is less than 0.671 in. (17.04 mm), discard backplate (6).
c. If thickness of backplate (6) marked No. 6 is less than 0.640 in. (16.26 mm), discard backplate (6).
5-358
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