TM-9-2320-272-10

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; OPERATOR'S MANUAL

SEPTEMBER 2004

CHANGE 2

TM-9-2320-272-10 - Page 320 of 481

TM 9-2320-272-10

2-211

(3)

Check tension adjustment of belts.

(4)

Check coolant hoses and lines for cracks, leaks, and security of

connections.

(5)

Add corrosion inhibitor compound to cooling liquid.

(6)

Check for correct tire inflation pressure. Do not reduce pressure if tires

are hot from driving.

(7)

Reduce lubrication intervals as specified in applicable LOs.

c.

Driving Vehicle.

(1)

Avoid continuous vehicle operation at high speeds. Avoid long, hard pulls

on steep grades with transfer case shift lever (6) in low.

(2)

Frequently check air cleaner indicator (7). If indicator shows red, perform

emergency air cleaner servicing (para. 3-8).

(3)

Frequently check engine coolant temperature gauge (8), engine oil

pressure gauge (10), and transmission oil temperature gauge (9). Engine or

transmission is overheating if any of the following conditions exist:

(a)

Coolant temperature gauge (8) indicates more than 210°F (99°C).

(b)

Oil pressure gauge (10) drops below 15 psi (103 kPa) on M939/A1

series vehicles and 10 psi (69 kPa) on M939A2 series vehicles, with engine at idle.

(c)

Transmission oil temperature exceeds 300°F (149°C) on oil

temperature gauge (9).

(4)

If engine overheating occurs:

NOTE

Do not raise vehicle hood.

Engine will cool faster at idle

with hood closed.

(a)

Park vehicle, allowing

engine to idle.

2-34. OPERATING IN EXTREME HEAT (Contd)