HYDRAULIC CONTROL SYSTEM FOR 4-SPEED AUTOMATIC TRANSMISSION

摘要

A hydraulic control system for 4-speed automatic transmission which is controlled by torque control hydraulic pressure and drive hydraulic pressure in regular succession and can provide a skip shift comprises a fluid pump (32), a pressure regulator valve (34) for regulating the line pressure generated at the fluid pump (32), a plurality of frictional elements (108, 62, 120, 84, 94, 100, 126) actuated by drive hydraulic pressure or reverse hydraulic pressure in accordance with the position of a valve spool of a manual valve (58), a first transmission control portion (D) having at least two valves (78, 86, 98) for supplying hydraulic pressure to at least one of the frictional elements, and a second transmission control portion (E) for selecting at least one of the frictional elements.