TM 9-2320-209-10-1 CHAPTER 2 DESCRIPTION AND DATA Section I. FUNCTIONAL DESCRIPTION 2-1. GENERAL. The 2 l/2-ton, 6x6 M44A1 and M44A2 series trucks are tactical ve- hicles designed for use on all types of roads, highways, and cross country terrain. They will ford hard bottom water crossings up to 30 inches deep without special fording equip- ment. The following paragraphs are provided to give the operator an overall understanding of the equipment and its main functions. The descriptive text is keyed to an overall equip- ment block diagram, which shows each functional group of the equipment as a block, Arrows are used to show the flow of power to and from each functional block on the diagram, WARNING This vehicle has been designed to operate safely and efficiently within the limits specified in this TM. Operation beyond these limits is prohibited IAW AR 70-1 without written approval from the Commander, U.S. Army Tank- Automotive Command, ATTN: AMSTA-CM-S, Warren, MI 48397-5000. 2-2. OVERALL EQUIPMENT FUNCTIONAL DESCRIPTION. (See Fig. 2-1,) a .Engine. The engine functions to supply power to move the truck and operate equip- ment and accessories. b. Clutch. The clutch by means of mechanical linkage, connects power produced by the engine, to the transmission. The clutch also separates power from the transmission when not needed, or while shifting transmission gears. c. Electrical System. The electrical system supplies electrical current to start the engine, operate lights, equipment and accessories, and to charge the batteries. d. Fuel System. The fuel system functions to store fuel in tanks, deliver fuel to the engine, as required, and return excess fuel to the tanks. e. Cooling System. The cooling system functions to remove excess heat produced while the engine is running, and to keep the engine at normal operating temperature. The cooling system also supplies heat to warm the cab or personnel compartment, when required. f. Exhaust System. The exhaust system functions to collect and remove exhaust gasses produced when the engine is operating. The exhaust system also supplies heat necessary to heat water in water tank trucks, when required. g. Transmission System. The transmission system gives the operator a choice of five forward gear combinations (speeds), reverse, and neutral position for operating the truck efficiently at all speeds and conditions. h. Transfer System. The transfer system sends power from transmission to propeller shafts to drive front and rear wheels. The system gives an additional gear combination (speed) for each transmission speed. i. Transmission Power Take-off System. This system transmits power to propeller shafts to operate auxiliary equipment. j. Transfer Power Take-off System. This system transmits power from the transfer unit to propeller shafts to operate auxiliary equipment and accessories. k. Propeller Shafts. Propeller shafts are used to transmit power from transmission to the transfer system and from transfer system to axles. Propeller shafts also transmit power from power take-off assemblies to auxiliary equipment and accessories. Change 2 2-1