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 hydraulic control apparatus including a first and second control valves switched to exert hydraulic pressure on a piston to press toward first position, a third and fourth control valves switched to exert hydraulic pressure on the piston to press toward second position and, a CPU. The CPU performs executing a first process controlling the control valves so that hydraulic pressure is exerted by switching of the first, second and third control valves or a second process controlling the control valves so that hydraulic pressure is exerted by switching of the second control valve and determining that the first control valve is failed when movement of the piston to the first position is not detected through the first process and determining that the third control valve is failed when movement of the piston to the first position is not detected through the second process.

An automatic transmission where the control portion controls the adjustment solenoid valve so that the circulation hydraulic pressure equals to a second circulation hydraulic pressure higher than the first circulation hydraulic pressure when the rotational speed difference between the output rotational speed of the fluid transmission device and the rotational speed of the driving source is more than the predetermined rotational speed.

A hydraulic control system for a motor vehicle transmission includes a pressure regulation subsystem in fluid communication with a pump for providing pressurized hydraulic fluid. A manual valve assembly is in direct fluid communication with the pressure regulation subsystem, and is moveable by an operator of the motor vehicle between at least park, neutral, drive, and reverse positions. A default disable valve assembly is in direct fluid communication with the manual valve assembly, a default disable solenoid, and a default select valve assembly. The manual valve assembly is in direct fluid communication with the default disable valve assembly which is in direct fluid communication with the default disable solenoid and the default select valve assembly. The default disable solenoid enables the default disable valve assembly to enable three default modes of operation and the default select valve assembly selects between two of the three default modes of operation.

A transmission for a machine is disclosed. The transmission may comprise a first torque path for transmission of torque from an input shaft to an output shaft, and a single clutch element along the first torque path. The transmission may further comprise a clutch actuator configured to actuate engagement of the clutch element, and a clutch pressure control (CPC) valve configured to permit a flow of hydraulic fluid to the clutch actuator when in an open position to cause the clutch actuator to actuate engagement of the clutch element. The transmission may further comprise a FMR valve having a failure position obstructing flow of the hydraulic fluid from the CPC valve to the clutch actuator when the CPC valve is in the open position. The FMR valve actuated by pilot pressure from a CPC valve that controls actuation of other clutch elements that are not on the first torque path.

A hydraulic circuit for a hybrid powertrain having an engine and an electric motor. The hydraulic control circuit includes a first pressure regulating valve configured to cooperate with a shift valve for selectively communicating a hydraulic fluid to a hydraulic piston actuator of a clutch assembly for engaging the engine to a driveline. The hydraulic control circuit further includes a second pressure regulating valve configured to selectively communicate a flow of hydraulic fluid to a cooling circuit for the cooling of the electric motor and to cooperate with a check valve and the shift valve to actuate the hydraulic piston actuator during a predetermined fail mode of the first pressure regulating valve, thus providing a limp-home mode by coupling the torque output from the engine to driveline of the vehicle.

A hydraulic circuit for a hybrid powertrain having an engine and an electric motor. The hydraulic control circuit includes a first pressure regulating valve configured to cooperate with a shift valve for selectively communicating a hydraulic fluid to a hydraulic piston actuator of a clutch assembly for engaging the engine to a driveline. The hydraulic control circuit further includes a second pressure regulating valve configured to selectively communicate a flow of hydraulic fluid to a cooling circuit for the cooling of the electric motor and to cooperate with a check valve and the shift valve to actuate the hydraulic piston actuator during a predetermined fail mode of the first pressure regulating valve, thus providing a limp-home mode by coupling the torque output from the engine to driveline of the vehicle.

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.

An automatic transmission where the control portion controls the adjustment solenoid valve so that the circulation hydraulic pressure equals to a second circulation hydraulic pressure higher than the first circulation hydraulic pressure when the rotational speed difference between the output rotational speed of the fluid transmission device and the rotational speed of the driving source is more than the predetermined rotational speed.

A hydraulic control system for a motor vehicle transmission includes a pressure regulation subsystem in fluid communication with a pump for providing pressurized hydraulic fluid. A manual valve assembly is in direct fluid communication with the pressure regulation subsystem, and is moveable by an operator of the motor vehicle between at least park, neutral, drive, and reverse positions. A default disable valve assembly is in direct fluid communication with the manual valve assembly, a default disable solenoid, and a default select valve assembly. The manual valve assembly is in direct fluid communication with the default disable valve assembly which is in direct fluid communication with the default disable solenoid and the default select valve assembly. The default disable solenoid enables the default disable valve assembly to enable three default modes of operation and the default select valve assembly selects between two of the three default modes of operation.