TM-9-2320-273-10

TRUCK, TRACTOR, LINE HAUL; LIGHT EQUIPMENT TRANSPORTER; TRUCK CHASSIS; MEDIUM EQUIPMENT TRANSPORTER

TECHNICAL MANUAL; OPERATOR’S MANUAL

DECEMBER 2012

TM-9-2320-273-10 - Page 129 of 452

Table 22. Transmission Ratio Selector, M915 through M920 - Continued.

Key

Control/Indicator

Function

Transmission Ratio

Selector (M915

through M920)

Place the ratio selector in neutral (N) to start the engine.

The engine will not start with the selector lever in any

other position. Place the ratio selector in R1 or R2 to

back up. R1 should be used for heavy loads or where a

slower reverse speed is required due to congestion or

other hazards. Move the ratio selector forward or

rearward to select the desired gear ratio position. The

transmission will remain in the previously selected

position until the ratio selector is moved into the notch

adjacent to the newly selected gear ratio. Progression

through the full range of 16 forward gear ratios may be

done two steps at a time up to 11th gear ratio. A built-in

inhibitor prevents more than a two step advance (or one

step advance from 11th–16th positions). The inhibitor

override is provided to allow selection of the proper gear

ratio for startup. This is done by pulling upward on the

ratio selector and may be used only when the truck is at a

standstill. Do not use the inhibitor override when the

truck is in motion.

The transmission is equipped with strip heaters to warm

the transmission during cold weather. The strip heaters

are thermostatically controlled for automatic operation at

temperatures below 5° F (-15° C). The indicator light on

the console illuminates with the key on when the strip

heaters are on. Do not operate the transmission until the

indicator light goes off.

TM 9-2320-273-10

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