TM 10-3930-659-20 Section III.  PRINCIPLES OF OPERATION Paragraph Page Number Paragraph Title Number 1-12 Drive Train System  ....................................................................................... 1-8 1-13 Service Brake System   .................................................................................. 1-8 1-14 Steering System  ............................................................................................ 1-9 1-15 Forklift Hydraulic System ............................................................................... 1-9 1-16 Electrical System............................................................................................ 1-9 1-17 On-board Crane.............................................................................................. 1-10 1-18 Forklift Winterization Package  ....................................................................... 1-10 1-12. DRIVE TRAIN SYSTEM. a. Engine.      The   engine   is   a   six-cylinder   turbocharged   diesel   which   supplies   rotational   power   to   the transmission.    The  cooling  system  is  pressurized  and  includes  a  thermostat,  controlled  bypass,  and  coolant  recovery bottle.  Engine lubrication is pressurized and oil is continuously cleaned by full-flow filters. b. Drive Dampener.  The drive dampener connects the engine to the transmission and absorbs torque spikes that could develop in the drive train. c. Transmission.  The transmission input shaft turns at engine speed.  A speed reduction takes place within the  transmission  according  to  the  speed  range  selected  by  the  operator.    The  direction  of  forklift  truck  travel  is  also determined by the transmission.  Both speed and direction selection are made by hydraulically operated clutches in the transmission. d. Drive  Shafts.    The  drive  shafts  transmit  rotation  of  the  transmission  output  to  the  front  and  rear  axles. Connections at both ends are made through universal joints to compensate for any misalinement. e. Front  and  Rear  Axles.    The  front  and  rear  axles  are  identical  in  operating  principle.    The  rear  axle  is different in that it oscillates 11 ° above and below horizontal.  Both axles drive whenever the transmission is engaged. Neither axle can be independently disconnected. 1-13. SERVICE BRAKE SYSTEM. a. Introduction.    The  service  brakes  are  foot  controlled,  hydraulic-type  brakes.    The  system  Is  supplied pressurized hydraulic oil by a pressure compensated pump that is driven by the engine. b. Fork/Brake   Hydraulic   Pump.      The   fork/brake   hydraulic   pump   is   a   variable   displacement,   pressure compensated, piston-type pump.  It supplies flow to both the service brake system and to the fork attachment cylinder circuits. c. Accumulators.    The  accumulators  in  the  brake  system  store  a  charge  of  pressurized  oil  which  allows  a number of brake applications In the event of pump failure or engine shutdown. d. Brake Valves.  The two brake valves are identical and are operated by separate foot pedals.  Depressing either foot pedal will cause all four wheel brakes to operate. 1-8