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 322 of 481

TM 9-2320-272-10

2-213

a.

General.

Be aware of vehicle overheating when operating in dusty or sandy

areas. Air cleaner, cooling system, and lubrication points will require frequent

servicing.

NOTE

• Do not use tire chains in soft sand.

• Use a second vehicle with winch to recover

vehicles stuck or sunk in sand.

b.

Driving Vehicle.

(1)

When starting in sand or soft ground, place transfer case shift lever (6)

in low range and transmission selector lever (5) in 1-2 (second) or 1-3 (third).

(2)

Deflate tires to 25 psi (172 kPa) only when operating off the road in

heavy rain. Inflate tires immediately to correct pressure when operation changes to

paved roads. Refer to table 1-10 for tire inflation data. Refer to paragraph 3-11 for

inflating tires using vehicle air system.

(3)

On M939A2 series vehicles, select SAND (8) on control panel (7). This

will automatically deflate tires unless 20 mph (32 km/h) is exceeded (15 mph (24

km/h) on M936A2 wrecker) for more than two minutes. CTIS will then automatically

inflate to cross-country pressure.

(4)

Accelerate slowly so wheels will not spin and dig into sand.

(5)

Inflate tires to normal pressures after vehicle has cleared deep sand

(table 1-10). On M939A2 series vehicles, press the desired mode select button on the

control panel (7).

(6)

When moving across a slope, choose the least angle possible. Keep

moving and avoid turning quickly.

(7)

Keep throttle steady after reaching desired speed.

(8)

Do not rock vehicle out of deep sand.

2-35. OPERATING IN DUSTY OR SANDY AREAS