Methods and systems for an electric drive axle of a vehicle are provided. An electric drive axle system includes, in one example a gear train configured to rotationally attach to an electric motor-generator, the gear train includes an output shaft having a clutch arranged thereon and configured to selectively rotationally couple a gear to the output shaft. The gear train further includes a lubrication channel extending between an output shaft and an axle shaft and including an outlet extending through the output shaft and opening into the clutch.

Methods and systems for an electric drive axle of a vehicle are provided. An electric drive axle system includes, in one example a gear train configured to rotationally attach to an electric motor-generator, the gear train includes an output shaft having a clutch arranged thereon and configured to selectively rotationally couple a gear to the output shaft. The gear train further includes a lubrication channel extending between an output shaft and an axle shaft and including an outlet extending through the output shaft and opening into the clutch.

A clutch device for a clutch system has an input member that rotates at a first speed. A friction drive system is disposed between the input member and an output member. The clutch device is selectively movable by a fluid actuator assembly, between an engaged position in which the friction drive system drives the output member to rotate at the first speed, and a disengaged position in which a viscous drive system rotates the output member at a second speed slower than the first speed. A variable viscous fluid supply assembly includes a viscous fluid storage chamber, a valve, and a valve actuator that selectively drives the valve to move between an open position and a closed position to control an amount of viscous fluid available to the viscous drive system, thereby varying the second speed.

A clutch device for a clutch system has an input member that rotates at a first speed. A friction drive system is disposed between the input member and an output member. The clutch device is selectively movable by a fluid actuator assembly, between an engaged position in which the friction drive system drives the output member to rotate at the first speed, and a disengaged position in which a viscous drive system rotates the output member at a second speed slower than the first speed. A variable viscous fluid supply assembly includes a viscous fluid storage chamber, a valve, and a valve actuator that selectively drives the valve to move between an open position and a closed position to control an amount of viscous fluid available to the viscous drive system, thereby varying the second speed.

Methods and systems for an electric drive axle of a vehicle are provided. An electric drive axle system includes, in one example a gear train configured to rotationally attach to an electric motor-generator, the gear train includes an output shaft having a clutch arranged thereon and configured to selectively rotationally couple a gear to the output shaft. The gear train further includes a lubrication channel extending between an output shaft and an axle shaft and including an outlet extending through the output shaft and opening into the clutch.

Methods and systems for an electric drive axle of a vehicle are provided. An electric drive axle system includes, in one example a gear train configured to rotationally attach to an electric motor-generator, the gear train includes an output shaft having a clutch arranged thereon and configured to selectively rotationally couple a gear to the output shaft. The gear train further includes a lubrication channel extending between an output shaft and an axle shaft and including an outlet extending through the output shaft and opening into the clutch.

A method of controlling an automatic transmission is provided. The automatic transmission includes first and second frictional engageable elements and a hydraulic mechanism. The method includes controlling a first hydraulic pressure control valve of the first element to adjust hydraulic pressure to a given value in a first period in response to the gear shift command and increase the hydraulic pressure until first friction plates engaged in a second period, and a second hydraulic pressure control valve of the second element to pre-charge in response to the gear shift command, maintain the hydraulic pressure at a lower value than a highest target value immediately after the pre-charging, and increase the hydraulic pressure until second friction plates engaged immediately after the maintaining the pressure, a time length of the first period being shorter than a time length between a start of the pre-charging and a start of the increasing the pressure.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying/discharging hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying/discharging hydraulic pressure to/from the chambers, and first and second oil paths communicating the valve with the chambers. The second surface has a larger area for receiving hydraulic pressure than the first surface. The method includes controlling the disengaged friction plates to be engaged by adjusting the hydraulic pressure to a first pressure in a first period in response to a gear shift command and adjusting the hydraulic pressure to a second pressure in a second period. The first pressure is changed depending on a state of the automatic transmission.

A transmission includes a case, a clutch pack, a piston. The case defines a bore that transitions along a step from a first to a second diameter. The piston is disposed within the bore. The piston has first and second seals that engage the case along the first and second diameters, respectively. The piston defines a chamber that is encompassed by the piston, the case, the first seal, and the second seal. The piston is configured to engage a clutch pack when hydraulic fluid is channeled into the chamber.

Methods and systems for an electric drive axle of a vehicle are provided. An electric drive axle system includes, in one example a gear train configured to rotationally attach to an electric motor-generator, the gear train includes an output shaft having a clutch arranged thereon and configured to selectively rotationally couple a gear to the output shaft. The gear train further includes a lubrication channel extending between an output shaft and an axle shaft and including an outlet extending through the output shaft and opening into the clutch.