TM 5-3805-254-20-1
POWER TRAIN - CONTINUED
The power created by the diesel engine is sent to the torque converter, which couples the diesel engine to the main
transmission by means of a hydraulic pressure actuated fluid coupling. The main transmission is an automatic or manually
shifted five-speed transmission, which is controlled by engine speed. The main transmission is coupled to an auxiliary
transmission by means of a propeller shaft. The auxiliary transmission is manually shifted and adds three output gear
ranges, underdrive, direct drive, and overdrive, which gives the dump truck 15 forward speeds and 3 reverse speeds. A
second propeller shaft is used to couple the auxiliary transmission to the power divider. The power divider allows the
driver to select power to the front rear axle or both front and rear axles to distribute power evenly to the rear wheels.
ENGINE
Four-stroke, turbocharged, in-line, six-cylinder internal-combustion diesel engine in which the heat of fuel is changed into
work in the cylinders of the engine. First the turbo forces air into the cylinder, then the air is compressed in a cylinder by a
piston. Then a charge of diesel fuel is sprayed into the cylinder by a fuel injection pump which distributes the diesel fuel to
six fuel injectors located in cylinder heads. The heat of compression causes the fuel to ignite and push the piston down.
The six pistons in the engine are connected to a crankshaft. Each time a piston is pushed down, it helps turn the
crankshaft and create turning power.
MAIN TRANSMISSION
The automatic transmission has five forward speeds, one reverse, and one neutral. The turning power of the engine is
sent to the transmission by a torque converter. Forward gear ranges can be manually selected or, when selector lever is
in D, gear changes are automatically performed.
TORQUE CONVERTER
Links the engine to the transmission. It multiplies the engine power to the transmission when driven.
POWER TAKEOFF
Mounted on left side of transmission and is engaged by a sliding gear. It supplies power from transmission to the dump
body hydraulic system oil pump when engaged.
1-23
