The present invention relates to a method for resolving a tooth-on-tooth position of a positive-locking shifting element of an automated manual transmission, in which gear steps of the automated manual transmission are changed by means of a pressure-medium-actuated shift actuator. If, during a change of a gear step of the automated manual transmission, a tooth-on-tooth position occurs at the interlocking shifting element, then the control of the pressure-medium-actuated shift actuator is varied in such manner as to resolve the tooth-on-tooth position. A control unit for carrying out the method is also disclosed.

Methods and systems for improving operation of a vehicle driveline that includes an engine and an automatic transmission with a torque converter are presented. In one non-limiting example, the engine may be stopped while a vehicle in which the engine operates is rolling. A transmission coupled to the engine may be shifted as the vehicle rolls so that vehicle response may be improved if a driver requests an increase of engine torque.

A system for controlling fluid flow to and from a clutch includes a motor, a pump, and a valve assembly. The valve assembly includes a housing defining an interior. The housing defines a first orifice operably coupled to the pump and a second orifice operably coupled to the clutch. The valve assembly also includes a piston operably coupled to the motor and disposed within the interior of said housing. The piston is movable between a first position for allowing the fluid flow between the first orifice and the second orifice, a second position for obstructing the fluid flow between the first orifice and the second orifice, and a third position for limiting the fluid flow between the first orifice and the second orifice. The valve assembly additionally includes a biasing member coupled to the piston. The biasing member biases the piston toward the first position.

A hydraulic assembly for a vehicle transmission includes a hydraulic pump for providing a system pressure within a hydraulic circuit, a pressure accumulator for temporarily supplying pressure to the hydraulic circuit, and a valve assembly for charging the pressure accumulator after a predetermined pressure threshold value of the system pressure has been reached or exceeded. The valve assembly is hydraulically connected between the pump and the pressure accumulator.

A hydraulic control device that includes a primary pressure control valve that has a first valve element and that regulates the primary pressure by varying a position of the first valve element in accordance with operation of a first electromagnetic actuator; a secondary pressure control valve that has a second valve element and that regulates the secondary pressure by varying a position of the second valve element in accordance with operation of a second electromagnetic actuator; and a fail-safe valve that varies the position of the first valve element such that the primary pressure is reduced when the first electromagnetic actuator and the second electromagnetic actuator become inoperable.

A drive axle assembly of a vehicle is provided. The drive axle assembly includes: a motor; a first shaft and a second shaft; a gearbox; a right shifting fork; a right inner ring-gear support; a right sun gear, a right inner planet gear, and a right outer planet gear; a left shifting fork; a left inner ring-gear support; a left sun gear and a left planet gear, where the left sun gear is configured to rotate coaxially with the right inner ring-gear support, and the left sun gear is configured to rotate synchronously with the second shaft; a driving gear, configured to rotate synchronously with the left planet gear by using a left planet support; and a differential connected with the driving gear.

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 method of controlling an automatic transmission mounted on a vehicle having an automatic engine stop mechanism for automatically stopping and restarting an engine, is provided. The transmission includes a piston having first and second surfaces, friction plates, engaging and disengaging hydraulic pressure chambers, a hydraulic pressure control valve for supplying/discharging hydraulic pressure to/from the chambers, first and second oil paths communicating the control valve with the chambers, a pressure reducing valve for preventing pressure of the disengaging chamber from exceeding a given set pressure, a hydraulic pressure supply device for supplying pressure to the control valve in the automatic stop state, and a mechanical oil pump for supplying pressure to the control valve while the engine is driving, the second surface having a larger pressure receiving area than the first surface. The method includes adjusting the set pressure to be lower in the automatic stop state than while driving.

A hydraulic arrangement for a vehicle transmission includes a hydraulic system path leading to a hydraulic system circuit with a system pressure, a hydraulic lubrication path leading to a hydraulic lubrication circuit with a lubrication pressure, and a branching point connected to an output side of the system and lubrication paths. A variable displacement pump or a pump combination includes at least two fixed displacement pumps hydraulically connected to an input side of the branching point, and a variable displacement pump or at least one fixed displacement pump are hydraulically connected to the output side of the branching point and integrated into the hydraulic system path.

A power transmission device that is mounted on a vehicle and provided with a transmission having a plurality of engagement elements for transmitting power from a motor to an axle, a case that accommodates the transmission, and a hydraulic control device that controls hydraulic pressure to the plurality of engagement elements.