Patent ID: 7611434

Claim:
A hydraulic controlling apparatus for an automatic transmission for vehicle, comprising: a hydraulic pump that outputs an operation oil pressure; a manual valve that generates a hydraulic pressure for forward running based on the operation oil pressure, when a valve position of the manual valve is switched in accordance with a shifting operation to a forward running position; a first solenoid valve device, that, when the first solenoid valve is in a normal state selectively supplies an output hydraulic pressure to plural hydraulic type frictionally engaging devices to establish plural speed-change steps of the automatic transmission; and a fail-safe gear step switching valve that (i) upon a failure state of the first solenoid valve, switches to a first position to establish a low-speed side fail-safe gear step or to a second position to establish a high-speed side fail-fail gear step, of plural speed-change steps of the automatic transmission, both the first position and the second position being set in advance based on the output hydraulic pressure from the solenoid valve device just before failure thereof occurs, so that the low-speed side fail-safe gear step or the high-speed side fail-safe gear step is selected in an alternative way, and (ii) is held at the second position based on a base pressure which is based on the operation oil pressure from the hydraulic pump, wherein the base pressure is supplied independent of the valve position of the manual valve.