Patent ID: 8224541

Claim:
A hydraulic control device for an automatic transmission, which is structured so as to establish a plurality of shift speeds by using a plurality of first system solenoid valves which are controlled by a first command system, and so as to establish a fail-safe running state where a primary pressure is supplied to a corresponding hydraulic servo of at least one of friction engagement elements which establishes a predetermined one of the shift speeds, or a fail-safe stopping state where a primary pressure to the hydraulic servos of all of the friction engagement elements is cut off, when a failure occurs in the first command system, the hydraulic control device, comprising a second system solenoid valve that is controlled by a second command system and that controls an output state of a signal pressures; a first computer that generates an electric command of the first command system; and a second computer in which at least wires thereof are formed in a separate system from that of the first computer, and that generates an electric command of the second command system, wherein the fail-safe traveling state and the fail-safe stopping state are switched by the signal pressure of the second system solenoid valve.