TM 10-3930-669-10 1-16.  MAST ASSEMBLY. The  mast  (1)  is  operated  hydraulically  by  seven  cylinders.    The  seven  cylinders  are  powered  by  the  dual  cartridge hydraulic pump (2).  The two tilt cylinders (3) tilt the mast 3 degrees forward and 6 degrees reverse.  The primary lift cylinder (4) and two secondary lift cylinders (5) raise the mast.  The pivot cylinder (6) swings the mast open up to 90 degrees to the right only.  The side shift cylinder (7) moves the carriage (8) left and right.  The pivot and tilt function speeds are restricted by internal orifices to maintain safe operating speeds.  All these functions are controlled by two joysticks (9) in the cab.  The joysticks operate the spools in control valves (10).  The backrest (11) provides stability for loads being transported. 1-11