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 4 of 481
TM 9-2320-272-10
Change 2
Warning c
• Do not use hand throttle while driving. The hand throttle will not disengage when
brakes are applied. Failure to do this will result in injury or death.
• Open van door slowly. Personnel may be on ladder. Use caution when using ladder.
• Use ground guide when backing up to parked semitrailer. Failure to do this will
result in damage to vehicle, injury, or death.
• Do not pull tractor forward beyond approach ramps until all air lines are
disconnected. Failure to do this will result in injury or death.
• Death or serious injury to soldiers, or damage to army equipment will occur if the
instructions in this procedure are not followed.
• Liquid surge results from liquid’s movement in partially-filled tanks, which may
result in loosing control of 5,000 gallon fuel tankers causing vehicle damage,
injury or death to personnel.
• On cross-country terrain, payload is limited to 3,000 gallons of fuel if the prime
mover is an M931/A1/A2 or M932/A1/A2 series 5-ton tractor. Failure to comply
may result in damage to vehicle or injury or death to personnel.
• Stopping distance is generally increased by ABS technology. ABS technology is
designed to perform a conventional braking technique called “stab” braking
automatically using wheel speed sensors. Drivers must understand they should
not pump the brakes on an ABS-equipped vehicle, as this will deactivate the
ABS. Drivers must also understand that by removing pressure from the brake
pedal, drivers can also deactivate the ABS. Failure to comply may result in
damage to vehicle or injury or death to personnel.
• When the ABS senses impending wheel lockup, the ECU will modulate the relays
which will repeat a “release and recharge” cycle of air in the brake chambers.
Unlike a car’s ABS, where you can feel this modulation on the brake pedal, you
will not feel any modulation of the brake pedal on an air brake system. When the
ABS does modulate, you will feel a jerking sensation of the vehicle as the brakes
rapidly release and lock. Failure to comply may result in damage to vehicle or
injury or death to personnel.
• M939 series vehicles have a conventional air brake system, which is very
sensitive. Drivers of these vehicles must be well-trained in operating tactical
vehicles with air brakes. Air brakes are unique because braking force is
proportional to pedal travel, but the driver does not experience resistance from
the brake pedal. An inexperienced driver may respond to lack of resistance by
applying too much force to brake pedal. Operators can be confident that M939
series trucks equipped w/ABS brakes have more than adequate brake capacity for
safe mountain terrain operations.
• Do not drive too fast for total weight of vehicle, amount of fuel in tanker, length
and angle of grade, road conditions, and weather. Failure to do so may result in
damage to vehicle or injury or death to personnel.
• Comply with warning signs indicating length and angle of grade. Failure to
comply may result in damage to equipment or injury or death to personnel.
WARNING SUMMARY (Cont’d)
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