A drop-in signal accumulator piston assembly replaces an original equipment (OE) signal accumulator piston in a vehicle transmission hydraulic circuit. The OE signal accumulator piston is positioned in a bore in a valve body that has an open end and a fluid port. The drop-in signal accumulator piston assembly includes a cylindrical sleeve having open first and second ends and a piston positioned in the sleeve. A spring is positioned in part in the piston and in part extending beyond and end of the piston. A plug is positioned in the bore adjacent the sleeve. The sleeve is positioned in the valve body bore, with the piston, and the spring, and the plug is positioned in the valve body bore to enclose the sleeve, the piston and the spring in the valve body bore. A method for replacing an original equipment (OE) signal accumulator piston in a transmission hydraulic circuit is disclosed.

A transmission case having a storage area inside for an assembling member, includes a first opening in the storage area; a seating portion provided in the storage area and on which the assembling member inserted from an opening direction of the first opening is to be seated; and a mirror-finished portion allowing an opposite portion of the assembling member facing the seating portion to be visually recognized when the assembling member is being inserted to the first opening from the opening direction.

A power-split hydro-mechanical hybrid transmission system with an automatic adjustment function includes an input member, a hydraulic transmission mechanism, a split mechanism, a convergence mechanism, an output member, a clutch assembly, and a brake assembly. The clutch assembly connects the input member to an input end of the split mechanism, connects an output end of the split mechanism to an input end of the hydraulic transmission mechanism and an input end of the convergence mechanism, and connects an output end of the hydraulic transmission mechanism to the output member. An output end of the convergence mechanism is connected to the output member. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input member and the output member. The power-split hydro-mechanical hybrid transmission system enables multi-mode continuously variable transmission and has energy reuse and emergency support functions.

A hydraulic control unit (10) for a transmission (36) of a motor vehicle drive train may include a housing top section (12), a first valve housing (14) having a first valve (60), and a second valve housing (16) having a second valve (62). The first valve (60) is aligned along a first direction (30) and the second valve (62) is aligned along a second direction (32), wherein the first direction (30) differs from the second direction (32).

A pressure regulator valve assembly for an automatic transmission includes a valve body, a valve chamber within the valve body, a valve piston disposed within the valve chamber, the valve piston having a valve channel, and a check valve disposed within the valve channel, the check valve is operable to permit fluid flow in the valve channel in a first direction and substantially prevent fluid flow in the valve channel in a second direction opposite to the first direction. An automatic transmission may include the pressure regulator valve assembly between a hydraulic pump and a torque converter, the pressure regulator valve assembly configured to control fluid flow between the hydraulic pump and the torque converter.

A valve arrangement structure of a control valve unit includes a control valve body to which oil is supplied from a main pump. The valve arrangement structure includes a pressure regulator valve that is arranged in the control valve body and regulates a pressure of discharged oil from the main pump to a line pressure, a pressure control valve that is arranged in the control valve body and regulates the pressure of the oil to a required pressure with the line pressure as a source pressure, and a first oil passage that is provided in the control valve body and connects the main pump and the pressure regulator valve. The pressure control valve is arranged on a second oil passage branched from the first oil passage.

Methods and systems for hydraulic actuation of axle system components are provided. A hydraulic system in an electric axle, is provided in one example, which includes a housing with a plurality of sections that enclose an electric motor and a gearbox, the system further includes a hydraulic pump that is coupled to the housing and configured to supply pressurized fluid to a solenoid valve through a plurality of fluid passages. The hydraulic system further includes a clutch in the gearbox configured to receive the pressurized fluid from the solenoid valve through a hydraulic passage internally routed through the housing.

A hydraulic system (1) for a transmission (2) of a motor vehicle (3) includes a pump system (5) with a first pressure outlet (6) and a second pressure outlet (7), a primary circuit (11), a secondary circuit (12), and a system pressure valve (8) that has a system pressure valve slide (9). A secondary pump pressure (P.sub.Psek) output from the second pressure outlet (7) of the pump system (5) is fed to a radial pressure surface (26) of the system pressure valve slide (9), and therefore an axial load based on the secondary pump pressure (P.sub.Psek) acts upon the radial pressure surface (26) of the system pressure valve slide (9) such that the system pressure valve slide (9) tends to move counter to a mechanical preload force out of a first switching position into a second switching position.

The disclosure reduces the number of factors to be considered in the switching control of the shift stages, thereby simplifying the switching control. In a control device of an automatic transmission, when a detection part detects that a shift position has been switched from one of a forward range and a reverse range to the other, among multiple hydraulic friction engagement mechanisms, a hydraulic pressure command value is fixed for the hydraulic friction engagement mechanisms that do not change the engaged state between the forward range and the reverse range, and the hydraulic pressure command value is variable based on a hydraulic pressure supplied to the hydraulic friction engagement mechanisms for the hydraulic friction engagement mechanisms that change the engaged state between the forward range and the reverse range.

A drop-in signal accumulator piston assembly replaces an original equipment (OE) signal accumulator piston in a vehicle transmission hydraulic circuit. The OE signal accumulator piston is positioned in a bore in a valve body that has an open end and a fluid port. The drop-in signal accumulator piston assembly includes a cylindrical sleeve having open first and second ends, one of the first and second ends defining a reduced diameter region, and a piston positioned in the sleeve. A spring is positioned in part in the piston and in part extending beyond and end of the piston. The sleeve is positioned in the valve body bore, with the piston, and the spring. A method for replacing an original equipment (OE) signal accumulator piston in a transmission hydraulic circuit is also disclosed.