TM 9-2320-360-10
Section III. PRINCIPLES OF OPERATION
1-12. SYSTEMS INTRODUCTION
This section provides a basic explanation of major systems on the HET Tractor. The power train,
electrical, air (pneumatic), winch, and central tire inflation systems are explained in this section.
1-13. POWERTRAIN
Power for the HET Tractor is generated by a two-stroke, V-type diesel engine coupled directly to an
automatic transmission. The engine is capable of 500 horsepower of braking.
The engine is equipped with an electronic control system that regulates fuel delivery to each injector as
well as governing engine speed for power takeoff operation. Engine sensors and engine performance
can be checked using a plug-in diagnostic reader.
Five forward drive ranges can be manually selected, depending on the terrain and conditions.
The
transmission will automatically downshift as engine speed and throttle position change.
Power from the transmission is directed to the transfer case and propeller shafts forward and rear. The
front axle and rear tridem axles are each equipped with planetary wheel ends. In low range, driver-
controlled lockouts in the differentials provide positive drive to all four axles.
1-20
