Methods and systems for a transmission are provided herein. In one example, a hydraulic system includes a lubrication valve included in a lubricant line and designed to adjust a flow of lubricant to a multi-disc wet clutch. The hydraulic system further includes a clutch line coupled to a clutch control valve, where the clutch line is in fluidic communication with a hydraulic fluid to a clutch actuator of the multi-disc wet clutch and a passive adjustment device of the lubrication valve and where the passive adjustment device transitions the lubrication valve between a limited flow state and an open flow state based on a pressure of the hydraulic fluid in the clutch line.

A double clutch unit for a transmission, having an outer clutch pack and an inner clutch pack each having a clutch pack input and a clutch pack output, wherein a clutch unit input hub rotationally fixed to the outer clutch pack input side and the inner clutch pack input side, a clutch unit inner output hub attached in fixed rotational relation to the outer clutch pack output side, a clutch unit outer output hub attached in fixed rotational relation to an inner clutch pack output side, and an oil distributor rotationally fixed to the inner clutch pack input side, are axially slidable relative to a stator, and a spring-loaded bolt is attached to the engine side of a clutch unit inner power output shaft maintaining the inner output hub, clutch unit outer output hub and oil distributor in axial alignment with respect to the stator.

A double clutch unit for a transmission, having an outer clutch pack and an inner clutch pack each having a clutch pack input and a clutch pack output, wherein a clutch unit input hub rotationally fixed to the outer clutch pack input side and the inner clutch pack input side, a clutch unit inner output hub attached in fixed rotational relation to the outer clutch pack output side, a clutch unit outer output hub attached in fixed rotational relation to an inner clutch pack output side, and an oil distributor rotationally fixed to the inner clutch pack input side, are axially slidable relative to a stator, and a spring-loaded bolt is attached to the engine side of a clutch unit inner power output shaft maintaining the inner output hub, clutch unit outer output hub and oil distributor in axial alignment with respect to the stator.

A driving force distribution device includes a lubrication path LP supplying lubricating oil from an oil inlet positioned on the case outside a cylinder into a hub of each clutch unit through an oil hole positioned between an external surface of the cylinder of each operation unit and a bearing supporting the same, between a spacer supporting the bearing and a snap ring supporting the spacer, between an internal diameter of the cylinder of each operation unit and an external diameter of a drum of each clutch unit, and in the drum of each clutch unit, allowing left and right lubrication paths for lubrication of left and right clutch units to have the shortest length, and simultaneously, each flow path to have an increased size.

A manufacturing method for a joint part in which a first metal piece and a second metal piece are joined to each other by performing welding by irradiating a high-energy beam to a joint surface on which the first metal piece and the second metal piece face each other, the first metal piece including a first flow path for passage of a fluid provided at a specific depth from a surface on a side exposed to the high-energy beam, the second metal piece including a second flow path for passage of the fluid provided at a specific depth from the surface on the side exposed to the high-energy beam, and the first flow path and the second flow path being coupled to each other on the joint surface.

A vehicle transmission includes a first rotating element, second rotating element, first retainer ring, and second retainer ring. The first rotating element has an exterior surface that defines a first ring groove. The second rotating element is configured to limit movement of friction plates during clutch engagement. The second rotating element is disposed about the exterior surface and has an interior surface that defines a second ring groove. The first retainer ring is disposed in the first ring groove. The second retainer ring is disposed in the second ring groove and thereby restricts movement of the first retainer ring in a radially outward direction.

A tandem drive axle mechanical shift assembly including a first shift rail assembly having a first shift rail actuated via a first pneumatic actuator, and a shift fork having a first end coupled with the first shift rail and a second end coupled with an engagement selector. A second shift rail assembly having a second shift rail actuated via a second pneumatic actuator, and a second shift fork having a first end coupled with the second shift rail and a second end coupled with an inter-axle differential lock-up clutch. First and second primary valves in fluid communication with a reservoir, and a secondary valve in fluid communication with the reservoir and in selective fluid communication with the second pneumatic actuator. A first actuation valve operated by the first shift rail and in selective fluid communication with the first and second primary valves, and the first and second pneumatic actuators.

A tandem drive axle mechanical shift assembly including a first shift rail assembly having a first shift rail actuated via a first pneumatic actuator, and a shift fork having a first end coupled with the first shift rail and a second end coupled with an engagement selector. A second shift rail assembly having a second shift rail actuated via a second pneumatic actuator, and a second shift fork having a first end coupled with the second shift rail and a second end coupled with an inter-axle differential lock-up clutch. First and second primary valves in fluid communication with a reservoir, and a secondary valve in fluid communication with the reservoir and in selective fluid communication with the second pneumatic actuator. A first actuation valve operated by the first shift rail and in selective fluid communication with the first and second primary valves, and the first and second pneumatic actuators.

A dual clutch transmission includes an input shaft having a first clutch having a first input disc carrier, a first output disc carrier, a first force transfer region, and a first actuation piston. The transmission includes a second clutch having a second input disc carrier, a second output disc carrier, a second force transfer region, and a second actuation piston. A first sub-transmission includes a first sub-transmission input shaft and a second sub-transmission has a second sub-transmission input shaft. The input shaft, the first input disc carrier, and the second input disc carrier are connected to one another for fixedly conjoint rotation. The first output disc carrier is connected to the first sub-transmission input shaft for fixedly conjoint rotation. The second output disc carrier is connected to the second sub-transmission input shaft for fixedly conjoint rotation. The second sub-transmission input shaft is arranged coaxially with and radially surrounding the first sub-transmission input shaft.

A dual clutch transmission includes an input shaft having a first clutch having a first input disc carrier, a first output disc carrier, a first force transfer region, and a first actuation piston. The transmission includes a second clutch having a second input disc carrier, a second output disc carrier, a second force transfer region, and a second actuation piston. A first sub-transmission includes a first sub-transmission input shaft and a second sub-transmission has a second sub-transmission input shaft. The input shaft, the first input disc carrier, and the second input disc carrier are connected to one another for fixedly conjoint rotation. The first output disc carrier is connected to the first sub-transmission input shaft for fixedly conjoint rotation. The second output disc carrier is connected to the second sub-transmission input shaft for fixedly conjoint rotation. The second sub-transmission input shaft is arranged coaxially with and radially surrounding the first sub-transmission input shaft.