PISTON 1H1694 - Caterpillar

Illustration 1 g00482154
Components of Priority Valve (1) Priority valve (2) Slug (3) Chamber (4) Poppet (5) Spool Assembly (6) Inlet passage (7) Outlet passageThe priority valve ensures that oil pressure is available for steering and braking first. Then, oil pressure is available for transmission operation. The priority valve is set to open to the transmission controls at 2925 kPa (424 psi).Priority valve (1) is located on the front of the bevel gear case. Oil from the oil pump enters inlet passage (6). Oil passes from inlet passage (6) through a hole in spool assembly (5) into chamber (3). Chamber (3) is located between slug (2) and poppet (4). When the oil pressure in chamber (3) becomes higher than priority valve setting, spool assembly (5) moves to the right. This allows pressure oil flow to outlet passage (7). From outlet passage (7), the pressure oil goes to the transmission selector and pressure control valve. The priority valve setting can be adjusted by the adjustment nut.