Method and control unit for freeing a vehicle by rocking

A method for rocking a vehicle free, the vehicle having a drive aggregate, a transmission comprising a plurality of shifting elements that are connectable between the drive aggregate and a drive output, and a hydrodynamic starting element with a converter, in each friction-locking gear of the transmission, a first number of the shifting elements of the transmission are engaged and a second number of the shifting elements are disengaged, the method comprising:

• when a function for rocking free is activated, carrying out the rocking free method as a function of an actuation of an accelerator pedal by a driver or as a function of a torque delivered by the drive aggregate as a function of the actuation of the accelerator pedal by the driver,
• controlling a frictional shifting element of the transmission that forms a frictional connection, in a gear used for the rocking free method, in such a manner that:
• when the actuation of the accelerator pedal by the driver or the torque delivered by the drive aggregate as a function of the actuation of the accelerator pedal by the driver is reduced, reducing a control pressure of the frictional shifting element of the transmission 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 as a function of the actuation of the accelerator pedal by the driver is increased, increasing the control pressure of the frictional shifting element of the transmission and operating the shifting element in a slipping mode.