TM 5-3805-258-24-1H Y D R A U L I C S Y S T E MS Y S T E M S O P E R A T I O NR I G H T S I D E O F T R A N S M I S S I ON1. Hydraulic pump.11. Pilot relief valve.The small pump section is the pilot section of the pump.This section has pilot relief valve (11) in it that keeps thepilot pressure to a maximum. The pilot oil has two uses. Itgoes to the hand metering unit (HMU) of the steeringsystem to operate the main valve of the steering controlvalve. It also goes through a check valve to selector andpressure control valve (2) for use in the implementhydraulic system. The selector and pressure control valvesends the oil onto lift and tilt pilot valve (3). Selector andpressure control valve (2) also provides pressure oil to liftand tilt pilot valve (3) to lower the bucket when the engineis off. The pilot oil does not go through the pilot valvewhen the control levers are in the HOLD position. When aR I G H T S I D E O F C AB3 . L i f t a n d t i l t p i l o t v a l v e . 1 2 . T i l t d e t e n t l e v e r . 1 3 .L i f t d e t e n t l e v e r . 1 4 . L i f t k i c k o u t s o l e n o i d . 1 5 . B u c k etpositioner solenoid.control lever is moved, a valve stem in the pilotvalve lets pilot oil go to lift and tilt control valve(7). The pilot oil then moves a valve spool in thelift and tilt control valve which lets oil from theimplement section of oil pump (1) go to either thelift or tilt cylinders to operate the bucket.The attachment (third) pilot valve gets its oilsupply from lift and tilt pilot valve (3). The attach-ment pilot valve operates the same way that thelift and tilt pilot valve operates.R I G H T S I D E O F H I T CH2. Selector and pressure control valve.The center section of hydraulic pump (1) is thesteering section. This oil is used for the operationof the steering cylinders to turn the machine.NOTE: For more information on the steering sys-tem see, 950B STEERING SYSTEM.The large section on the drive end of hydraulicpump (1) is the implement section. It provides theoil to operate the tilt and lift cylinders. The oil goesto lift and tilt control valve (7). This valve is anF R O N T O F L O A D E R F R A ME4. Tilt cylinder. 6. Lift cylinder (left side). 7. Lift and tiltcontrol valve. 16. Main relief valve. 17. Head end tilt reliefvalve. 18. Rod end tilt relief valve.3-90
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business