A gear engagement method for a hybrid vehicle includes detecting whether or not baulking occurs when a controller attempts to engage a target gear via a synchronizer. The gear engagement method also includes checking, by the controller, for a stationary state of the vehicle if the result of the detecting shows that there is baulking. The gear engagement method also includes engaging, by the controller via the synchronizer, a different gear that shares a same input shaft with the target gear if the result of the checking shows that the vehicle is in a stationary state. The gear engagement method also includes reattempting an engagement with the target gear after disengaging the different gear. The disengaging and the reattempting are performed by the controller via the synchronizer after the engaging.

A gear engagement method for a hybrid vehicle includes detecting whether or not baulking occurs when a controller attempts to engage a target gear via a synchronizer. The gear engagement method also includes checking, by the controller, for a stationary state of the vehicle if the result of the detecting shows that there is baulking. The gear engagement method also includes engaging, by the controller via the synchronizer, a different gear that shares a same input shaft with the target gear if the result of the checking shows that the vehicle is in a stationary state. The gear engagement method also includes reattempting an engagement with the target gear after disengaging the different gear. The disengaging and the reattempting are performed by the controller via the synchronizer after the engaging.

A hydraulic pressure control device of a vehicle driving device, the hydraulic pressure control device includes a range switcher having a first signal solenoid valve capable of supplying a first signal pressure and a spool switchable between a first position reached via the first signal pressure and a second position reached via a biasing force of a biasing member.

A hydraulic pressure control device of a vehicle driving device, the hydraulic pressure control device includes a range switcher having a first signal solenoid valve capable of supplying a first signal pressure and a spool switchable between a first position reached via the first signal pressure and a second position reached via a biasing force of a biasing member.

A device and method for operating a fluid-guiding device, including an electrically operated fluid pump, which delivers fluid from a fluid sump of the fluid-guiding device and supplies it to at least one fluid consumer. A fluid volume in the fluid sump as well as a current intensity of the electric current taken up by the fluid pump and modeled on the basis of the rotational speed of the fluid pump are ascertained, and a comparison value is determined from the modeled current intensity. A deficient fluid supply of the fluid-guiding device is inferred if the fluid volume is greater than a threshold value and a measured current intensity of the electric current taken up by the fluid pump is less than the comparison value.

A device and method for operating a fluid-guiding device, including an electrically operated fluid pump, which delivers fluid from a fluid sump of the fluid-guiding device and supplies it to at least one fluid consumer. A fluid volume in the fluid sump as well as a current intensity of the electric current taken up by the fluid pump and modeled on the basis of the rotational speed of the fluid pump are ascertained, and a comparison value is determined from the modeled current intensity. A deficient fluid supply of the fluid-guiding device is inferred if the fluid volume is greater than a threshold value and a measured current intensity of the electric current taken up by the fluid pump is less than the comparison value.

Provided is an automatic transmission with which a switching mechanism thereof is hardly damaged even if the hydraulic pressure supplied to a hydraulic pressure control circuit temporarily changes. A control part ECU of the automatic transmission TM switches the first brake B1 to the reverse rotation preventing state when a signal indicating that the slider is at a position corresponding to the reverse rotation preventing state is received while the control unit ECU recognized that it has switched the first brake B1 to the fixed state.

The present invention provides an automatic transmission capable of properly judging faults of a switching mechanism. A control part ECU of the automatic transmission TM has an actual change gear ratio calculating part 10 and a fault judging part 11. Under a condition that the control part ECU has recognized that the first brake device B1 is switched to a reverse rotation preventing state, if the actual change gear ratio is kept to be an actual change gear ratio prior to a reduce of a rotational speed of a drive source ENG when the rotational speed of the drive source ENG is reduced, then the fault judging part 11 judges that a first brake B1 has a fault.

The present invention provides an automatic transmission capable of properly judging faults of a switching mechanism. A control part ECU of the automatic transmission TM has an actual change gear ratio calculating part 10 and a fault judging part 11. Under a condition that the control part ECU has recognized that the first brake device B1 is switched to a reverse rotation preventing state, if the actual change gear ratio is kept to be an actual change gear ratio prior to a reduce of a rotational speed of a drive source ENG when the rotational speed of the drive source ENG is reduced, then the fault judging part 11 judges that a first brake B1 has a fault.

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.