An automated manual transmission, comprising: a transmission control unit, a shift rod movable between a predetermined first position in which it engages a first gear combination of the transmission, a predetermined second position in which it engages a second gear combination of the transmission, and a predetermined neutral position in which it does not engage any gear, an actuator for moving the shift rod between the first position, the second position and the neutral position by applying a fluid pressure acting on the shift rod in response to signals from the transmission control unit, mechanical engagement means for maintaining the first and second positions of the shift rod without applying any fluid pressure by means of the actuator,
wherein the transmission is adapted to maintain the neutral position of the shift rod solely by applying fluid pressure acting on the shift rod.

A control device of a vehicle power transmission device including a first power transmission path transmitting power by engaging a first clutch, a sub-clutch and a second power transmission path transmitting power by engaging a second clutch each disposed between an engine and drive wheels and parallel to each other, the device including a fail-safe valve for preventing simultaneous engagement of the first and second clutches, the fail-safe valve configured to be switched to a fail-safe spool position preventing simultaneous engagement of the first and second clutches by a hydraulic pressure of a hydraulic fluid supplied to the first clutch or an output pressure of a first electromagnetic valve controlling the hydraulic pressure and the hydraulic pressure of the hydraulic fluid supplied to the second clutch or an output pressure of a second electromagnetic valve controlling the hydraulic pressure, the second electromagnetic valve configured to increase the output pressure.

A fluid pressure control circuit for a transmission, includes plural electromagnetic valves each switching one of engagement elements between an engaged state and a disengaged state, plural passages configured to connect the engagement elements to a fluid pressure source, a first electromagnetic valve corresponding to one of the electromagnetic valves and switching one of the engagement elements between the engaged and disengaged states, a second electromagnetic valve corresponding to another of the electromagnetic valves and switching another of the engagement elements between the engaged and disengaged states, and a shut-off valve, when the first electromagnetic valve and the second electromagnetic valve are open, closing the passages among the first electromagnetic valve, the engagement elements switched by the first electromagnetic valve and the fluid pressure source with the use of the fluid pressure to establish a closed state, and maintaining the closed state with the use of the fluid pressure.