TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 197 of 1313
LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - Continued
Table
2.
Description of Interior Cab Components.
1
INSTRUMENT PANEL
- Houses controls and indicators.
2
TRANSMISSION SELECTOR LEVER
- Manual control to select driving gear.
3
SPRING BRAKE OVERRIDE SWITCH
- Pressed in to release spring brakes independent of the
mechanical parking brake for tests and adjustments. Can be used to release spring brakes in the event a
leak or stoppage occurs in lines between primary and spring brake reservoirs, or primary system air shutoff
valve is closed.
4
TRANSMISSION POWER TAKEOFF (PTO) LEVER
- Used on M925/A1/A2, M928/A1/A2, M929/A1/A2,
M930/A1/A2, M932/A1/A2, and M936/A1/A2 model vehicles only. Provides hydraulic power for front winch
and/or dump body operation.
5
WINCH CONTROL LEVER
- Provides control of winch unwinding and winding operations from inside the
cab.
6
PASSENGER SEAT
- Combination two-person crew seat, battery box, and storage box. Seats are
equipped with two sets of seatbelts, the battery box houses four batteries, and the storage compartment
stores technical manuals.
NOTE:
Ensure companion seatbelts are not caught inside battery box.
7
TRANSFER CASE SHIFT LEVER
- Pushed down to shift transfer case into HIGH gear, center position
for NEUTRAL, and up position for LOW gear. When transfer case is placed in LOW, it will automatically
engage six-wheel drive. In HIGH, the instrument panel-mounted front-wheel drive lock-in switch must be
used to achieve six-wheel drive operation.
8
SPRING BRAKE CONTROL SWITCH
- Senses the position of the parking brake control lever and signals
the spring brakes to engage when the lever is up and disengage when it is down. Spring brakes can be
tested independently from parking brake by raising this switch without pulling up the parking brake control
lever (TM 9-2320-272-10).
9
(a) DUMP BODY CONTROL LEVER
- Used on M929/A1/A2 and M930/A1/A2 to control raising (pulled
back) and lowering (pushed forward) of dump body.
(b) TRANSFER CASE POWER TAKEOFF (PTO)
- Used on M936/A1/A2 to control the hydraulic pump
that delivers hydraulic pressure to the rear winch and crane. A spring brake air dump switch is installed on
the lever when used on these vehicles, which engages the spring brakes. To override this feature during
self-recovery operation with the rear winch, the driver must depress and hold the PTO spring brake override
air switch on the instrument panel.
10
DUMP BODY CONTROL LEVER SAFETY LATCH
- Secures dump body control lever or transfer case
PTO in NEUTRAL when not in use.
11
PARKING BRAKE CONTROL LEVER
- Pulled up to set mechanical brake on output of transfer case and
to engage the spring brakes, and down to disengage the brakes. Knob on top of handle is turned clockwise
to increase braking action on the output of transfer case, and counterclockwise to decrease braking action.
Spring brakes engagement is controlled by the spring brake control switch located on the back of the lever.
TM 9-2320-272-23-1
0002
0002-16
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