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 194 of 1313
LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - Continued
Table
1.
Description of Exterior Major Components.
1
LIFTING SHACKLE(S)
- Permit vehicle to be towed by another vehicle or used for tiedown attachment
when transporting vehicle.
2
ENGINE
- There are two different Cummins model engines used, the NHC 250 (M939/A1 series vehicles)
and 6CTA8.3 diesel (M939A2 series vehicles), which provide mechanical power to the vehicle and engine-
driven subsystems.
3
TRANSMISSION
- The Allison MT654CR automatic, used on all M939/A1/A2 series vehicles, adapts the
engine's output for a varying range of operating speeds.
4
PRIMARY AND SECONDARY AIR RESERVOIRS
- Provides storage of compressed air and isolation
between air subsystems.
5
TRANSFER CASE
- Directs the engine and transmission output to the specified axles and/or auxiliary
equipment.
6
WET TANK RESERVOIR
- Provides reserve storage of compressed air created by the air compressor or
external source when demand is low and releases it when required. This lessens the cycling of the engine-
driven air compressor.
7
REAR PROPELLER SHAFT(S)
- Transmits power between transfer case and forward-rear axle
assemblies, and between forward-rear and rear-rear axle assemblies.
8
UNIVERSAL JOINT(S)
- Provides a flexible point between a component and the propeller shafts. This
allows components that cannot maintain precision alignment to transfer power from one point to another,
without undue stress or breakage.
9
SERVICE BRAKE CHAMBER
- Mechanical brake actuator that is activated by applying air pressure to
an expandable cylinder, causing it to apply braking force to the brake drum.
10
REAR BOGIE
- The suspension system comprised of both rear axles, upper and lower torque rods,
springs, and seats that support the rear vehicle weight.
11
SPRING BRAKE CHAMBER
- Mechanical brake actuator that is spring-loaded to apply brakes when air
is low or not present. During normal vehicle operation, air piston counteracts the spring tension and allows
the brakes to release. Spring brakes can be bypassed by pushing in the spring brake OVERRIDE switch
on the instrument panel, or released using procedures found in TM 9-2320-272-10.
12
TOWING PINTLE
- Provides a secure quick-connect/disconnect for towing vehicles or equipment.
13
REAR DIFFERENTIAL(S)
- Bi-directionally transfer power from the propeller shafts to the axles, and
provide a straight-through connection to power additional propeller shafts.
14
FUEL TANK(S)
- Provides storage of fuel.
TM 9-2320-272-23-1
0002
0002-13
Back to Top
