OPERATING UNDER RAINY OR HUMID CONDITIONS (Contd)
Do not overtighten plastic valve; damage may result and fuel may leak.
On M939A2 series vehicles, loosen drainvalve (5) on bottom of fuel filter/water separator (4), drain
water into suitable container, and close drainvalve (5) when clean fuel is visible.
If fuel is not clear before approximately one qt (0.946 L) has drained, notify unit maintenance.
After draining has been completed, prime the fuel system (para. 3-8).
Do not spin wheels when placing vehicle in motion in heavy rain or muddy conditions. If necessary, place
transfer case shift lever (7) in low range and transmission selector lever (6) in 1-3 (third) to obtain a slow, firm start.
Pump brakes gradually when slowing or stopping vehicle on wet
pavement. Sudden stops will cause vehicle wheels to lock, engine to
stall, and loss of power steering. Failure to do this may result in injury or
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.
On M939A2 series vehicles, select SAND (9) on control panel (8). 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
automatically inflate to cross-country pressure.