Method and control unit for freeing a vehicle by rocking

A method for rocking a vehicle free,

• wherein the vehicle comprises:
• a drive aggregate (2),
• a transmission (4) comprising a plurality of shifting elements (10) connected between the drive aggregate (2) and a drive output (3), and
• a hydrodynamic starting element (5) with a converter (6),
• in each friction-locking gear of the transmission (4), a first number of shifting elements (10) of the transmission (4) are engaged and a second number of shifting elements (10) are disengaged,
• such that when a function for rocking free is activated, the rocking free process is carried out and for that purpose, as a function of an actuation of an accelerator pedal (11) by the driver or as a function of a torque delivered by the drive aggregate (2) as a function of the actuation of the accelerator pedal by the driver, a frictional shifting element (10) of the transmission (4) that forms the frictional connection, in a gear used for the rocking free process, is controlled in such a manner that:
• when the actuation of the accelerator pedal by the driver or the torque delivered by the drive aggregate (2) as a function of the actuation of the accelerator pedal by the driver is reduced, a control pressure of the frictional shifting element (10) of the transmission (4) is reduced down to a filling pressure or a pressure that corresponds to the filling pressure, and
• when the actuation of the accelerator pedal by the driver or the torque delivered by the drive aggregate (2) as a function of the actuation of the accelerator pedal by the driver is increased, the control pressure of the frictional shifting element (10) of the transmission (4) is increased and the shifting element is operated in a slipping mode.