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 398 of 836
TM 9-2320-272-24-4
5-60. TRANSMISSION OIL PRESSURE TESTING (Contd)
15.
Remove pipe plug (4) from auxiliary governor pressure port (3) and install in main pressure port (5).
16.
Install pressure gauge and hose (2) in auxiliary governor pressure port (3).
17.
Start engine and check pressure port connection for leaks.
18.
Check transmission oil level.
19.
Place transmission shift lever in 1-5 (drive) position and operate engine at 1,650 rpm. Note reading
on pressure gauge.
20.
If pressure is not 82-91 psi (565-627 kPa), repair transmission (1) as necessary
21.
Stop engine and disconnect pressure gauge and hose (2) from auxiliary governor pressure port (3).
22.
Remove pipe plug (4) from main pressure port (5).
NOTE
Only M936/A1/A2 vehicles are equipped with check valve.
23.
Install check valve (8) and adapter (9) in auxiliary governor pressure port (3). Ensure bleed hole end
of check valve (8) is inserted into pressure port (3) first.
24.
Install governor pressure line (10) on adapters (9) and (12).
25.
Install adapter (7) in main pressure port (5).
26.
Install main pressure line (6) on adapters (7) and (11).
27.
Start engine and check pressure port connections for leaks.
28.
Check transmission oil level.
29.
Install transmission-to-transfer case propeller shaft (para. 3-148).
c. Automatic Shift Speed Test
1.
Road test vehicle and record engine rpm at shift points (TM 9-2320-272-10).
2.
With vehicle in operation, shift transmission through the range sequence. See table 5-17 for lever
range sequence.
3.
Check recorded engine shift point rpm with table 5-17.
4.
If shift points are incorrect, check modulator adjustment (para. 5-61). If modulator adjustment does
not correct shift speed, repair transmission (1) as necessary.
Table 5-17. Transmission Shift Point Check.
SELECTOR
LEVER RANGE
1-2
1-3
1-4
1-5 (drive)
THROTTLE
Fully open
AUTOMATIC
ENGINE
SHIFTING
(RPM)
1-2
1,900-2,050
2-2
1,900-2,050 (before converter lock-in)
2-2
1,600-1,825 (after converter lock-in)
2-3
2,000-2,150
3-4
2,030-2,140
4-5
2,015-2,130
5-392
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