Abstract: An automatic transmission control system for an automotive vehicle comprising fluid pressure operated clutch and brake servos that establish and disestablish plural torque delivery paths between the engine of the vehicle and a driven member, the control system having a pressure regulator for maintaining an optimum pressure level, a throttle solenoid valve, ratio shift controlling solenoid valves and means for replacing the functions of the throttle solenoid valve and the shift controlling solenoid valves in the event that a control voltage failure or a valve malfunction should occur.

Abstract: A control system for an automatic transmission including pressure actuated clutches and brakes adapted to control ratio changes in a planetary gear system comprising multiple function shift control valves disposed between a pressure source and pressure actuated servos for the clutches and brakes and solenoid valves under the control of a microprocessor for developing solenoid valve signals that control actuation of the shift control valves, the shift control valves being interactive, one with respect to the other, to effect multiple shift functions in response to selective actuation of the solenoid valves whereby the number of solenoid valves required is reduced and the hydraulic circuitry for the valve elements is simplified.