A method for rocking a vehicle free. The vehicle comprises a drive aggregate (2), a transmission (4), shifting elements (10), and a starting element (5). The rocking free process is carried out as a function of actuation of an accelerator pedal (11) by the driver or a torque delivered by the drive aggregate (2) as a function of the actuation of the accelerator pedal. The shifting element (10) is controlled such that reduced actuation of the accelerator pedal or reduced torque delivered by the drive aggregate (2), reduces a control pressure of the shifting element (10) of the transmission (4) down to a filling pressure or a pressure that corresponds to the filling pressure, and increased actuation of the accelerator pedal or increased torque delivered by the drive aggregate (2), increases the control pressure of the shifting element (10) and the shifting element is operated in a slipping mode.

A hydraulic device for a work vehicle includes a device body, a plug, and a filler insert. The device body includes a wall structure between surfaces defining internal passages including an access passage having a first diameter extending from an access opening in the device body to a hydraulic fluid passage extending through the wall structure from an entry opening in a first surface to an exit opening in a second surface to deliver hydraulic fluid through the wall structure. A plug is mounted to the device body to close the access opening. A filler insert is proximate the plug and has a shank having a circular cross-section of a second diameter that is less than the first diameter so as to be decoupled from the inner wall surface of the access passage. An annular space around the shank in the access passage allows the hydraulic fluid to encircle at least a part of the shank of the filler insert.

A hydraulic device for a work vehicle includes a device body, a plug, and a filler insert. The device body includes a wall structure between surfaces defining internal passages including an access passage having a first diameter extending from an access opening in the device body to a hydraulic fluid passage extending through the wall structure from an entry opening in a first surface to an exit opening in a second surface to deliver hydraulic fluid through the wall structure. A plug is mounted to the device body to close the access opening. A filler insert is proximate the plug and has a shank having a circular cross-section of a second diameter that is less than the first diameter so as to be decoupled from the inner wall surface of the access passage. An annular space around the shank in the access passage allows the hydraulic fluid to encircle at least a part of the shank of the filler insert.

A hydraulic system for an automatic transmission of a motor vehicle. A high pressure circuit in which a pressure accumulator, at least one clutch as well as gear selectors and at least one hydraulic pump are arranged, which can be controlled by an electronic control unit. The pressure accumulator can be connected to a hydraulic positioning cylinder via at least one hydraulic path, wherein a control valve that can be controlled by the control unit is arranged upstream thereof, with which a hydraulic pressure at the hydraulic positioning cylinder can be adjusted, and which control valve can be moved between two through-flow positions in order to move a piston in opposing piston strokes via opposing piston travel paths as well as piston speeds in the hydraulic positioning cylinder.

A hydraulic system for an automatic transmission of a motor vehicle. A high pressure circuit in which a pressure accumulator, at least one clutch as well as gear selectors and at least one hydraulic pump are arranged, which can be controlled by an electronic control unit. The pressure accumulator can be connected to a hydraulic positioning cylinder via at least one hydraulic path, wherein a control valve that can be controlled by the control unit is arranged upstream thereof, with which a hydraulic pressure at the hydraulic positioning cylinder can be adjusted, and which control valve can be moved between two through-flow positions in order to move a piston in opposing piston strokes via opposing piston travel paths as well as piston speeds in the hydraulic positioning cylinder.

A hydraulically actuatable shift element (100) includes a clutch piston (101), a fast fill piston (102), a fast fill valve (103), a fast fill pressure chamber (126), and a clutch pressure chamber (117). The fast fill valve (103) includes a sealing body (132) and a control body (131). Before the actuation of the shift element (100), the sealing body (132) is in a first switching position, in which the fast fill pressure chamber (126) is connected to a pressurized oil source (108) and, after the actuation of the shift element (100) in a second switching position, seals off the fast fill pressure chamber (126) with respect to the rest of the hydraulic system. The control body (131) has a first pressure surface (A18) and a second pressure surface (A19), wherein, in the first switching position, only the first pressure surface (A18) is pressurizable from the pressurized oil source (108). The fast fill valve (103) is configured such that, in the second switching position or between the first switching position and the second switching position of the control body (131), the second pressure surface (A19), in addition to the first pressure surface (A18), is pressurizable.

A hydraulically actuatable shift element (100) includes a clutch piston (101), a fast fill piston (102), a fast fill valve (103), a fast fill pressure chamber (126), and a clutch pressure chamber (117). The fast fill valve (103) includes a sealing body (132) and a control body (131). Before the actuation of the shift element (100), the sealing body (132) is in a first switching position, in which the fast fill pressure chamber (126) is connected to a pressurized oil source (108) and, after the actuation of the shift element (100) in a second switching position, seals off the fast fill pressure chamber (126) with respect to the rest of the hydraulic system. The control body (131) has a first pressure surface (A18) and a second pressure surface (A19), wherein, in the first switching position, only the first pressure surface (A18) is pressurizable from the pressurized oil source (108). The fast fill valve (103) is configured such that, in the second switching position or between the first switching position and the second switching position of the control body (131), the second pressure surface (A19), in addition to the first pressure surface (A18), is pressurizable.

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 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 piston-cylinder assembly (1) has a cylindrical housing (3), with a main piston (2) and at least one trailing piston (11, 12). The trailing piston (11, 12) is axially guided on a cylindrical outer lateral face (38) of the main piston (2). The trailing piston (11, 12) has a thrust portion (13, 14) at one end near a piston web on the main piston, The thrust portion extends axially inward toward the piston web (10) A travel limiter (28) on the cylindrical housing limits a travel range of the trailing piston (11, 12) Under pressure, the trailing piston (11, 12) follows the main piston (2) until the trailing piston (11, 12) hits the travel limiter (28). The thrust portion (13, 14) of the trailing piston (11, 12) is shaped to fit into an associated recess (30, 31) in the piston web with a positive lock.