Hydraulic-pressure control circuit for vehicular automatic transmission, has switching valve switched between two positions based on change in position of manual valve when electromagnetic valves stop working

摘要

The circuit (130) has a switching valve (132) switched between two positions based on the change in position of a manual valve when electromagnetic valves (38,84,86,90,92) stop working, such that clutches (CL1,CL2) and brakes (B1-B3) are operated at engaged states at predetermined combinations to establish two speeds. The clutches and brakes are operated at engaged states when supplied with hydraulic fluids from a hydraulic pump (29). An Independent claim is also included for a hydraulic-pressure control method.