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 460 of 836
5-64. DIFFERENTIAL
TM 9-2320-272-24-4
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
Remove six screws (6), lockwashers (7), cover (8), and shims (9) from differential carrier housing (1).
Remove safety wire (15), three screws (16), and retaining plate (14). Discard safety wire (15).
Using two jacking screws (17), remove bearing retainer (13) and shim pack (12) from shaft (11)
and shaft housing shoulder (10).
Remove eight screws (4), washers (5), mainshaft (3), and shim pack (2) from differential carrier
housing (1).
NOTE
If adjustment is needed to correct bevel ring gear and pinion gear
contact pattern, make initial shim changes of at least 0.010 in.
(0.25 mm).
For contact pattern of type in step 51, add shims to shim pack (2) and remove shims from shim
pack (12).
For contact pattern of type in step 52, add shims to shim pack (12) and remove shims from shim
pack (2).
For contact pattern of type in step 53, remove shims from pack (2) and add shims to shim pack (12).
For contact pattern of type in step 54, remove shims from shim pack (12) and add shims to shim
pack (2).
Using dial indicator, check backlash (20) of bevel ring gear (18) and pinion gear (19).
Backlash (20) should be 0.005-0.015 in. (0.127-0.381 mm).
NOTE
If backlash needs correction, perform steps 55, 56, 57, and 58.
If bevel ring gear and pinion gear backlash are within limits, go
to step 71.
If bevel ring gear and pinion gear backlash are not within
limits, perform steps 65 and 66.
If backlash (20) is less than limits, add equal amounts of shims to shim packs (2) and (12).
If backlash (20) is greater than limits, remove equal amounts of shims from shim packs (2) and (12).
Carefully place mainshaft (3) and shim pack (2) in differential carrier housing (1) and install with
eight washers (5) and screws (4). Tighten screws (4) 93-120 lb-ft (126-163 N•m).
Carefully align shim pack (12) to shaft housing shoulder (10) and press on bearing retainer (13)
over shaft (11).
Install retaining plate (14) on sheet (11) with three screws (16). Tighten screws (16) 42-54 lb-ft (57-
73 N•m). Fasten new safety wire (15) to all three screws (16).
Carefully align shims (9) to bearing retainer (13) and install cover (8), shims (9), retainer (13),
and shims (12) on shoulder (10) of carrier housing (1) with six new lockwashers (7) and screws (6).
Tighten screws (6) 60-100 lb-ft (81-136 N•m).
5-454
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