TM 9-2320-279-10-1
2-174
Change 8
M977 Through M985 General Operating Procedures (Cont)
2-11. DRIVE VEHICLE (CONT).
l. Drive Up Steep Grades. Press and hold throttle treadle (1) all the way
down as vehicle moves up grade. Transmission will automatically downshift
gears as needed.
m. Drive Down Steep Grades.
CAUTION
S
Do not allow speed to go above 2100 rpm when
driving downhill or damage to engine can result.
S
Engine brake operates best when engine speed is
between 1650 and 2100 rpm. Transmission torque
converter lockup valve may disengage below 1650
rpm resulting in loss of engine power.
(1)
Set transmission range selector (2 or 2.1) to lower range as needed to
keep engine speed on tachometer (3) between 1650 and 2100 rpm.
WARNING
Do not press service brake treadle hard three or four
times in a row. Air supply will be used up and service
brakes will not work until air pressure is built up again.
Loss of braking ability can result in serious personal
injury or death.
(2)
Use service brake (4) as needed to control vehicle speed.
(3)
Use engine brake as needed (para 2-11f).
