Method for operating a vehicle drive train having a driving machine and having a transmission apparatus having a plurality of shift elements

A method for operating a vehicle drive train (1) comprising:

• a drive machine (2);
• a transmission apparatus (3) comprising a plurality of shift elements (A to F) which are either engaged or disengaged in a power flow for implementing different transmission ratios (“1” to “8”) within the transmission apparatus (3);
• and
• an output drive,
• the output drive being coupled to a transmission output shaft (7) of the transmission apparatus (3) and the drive machine (2) being coupled to a transmission input shaft (6) of the transmission apparatus (3),
• upon a request to interrupt the power flow in the transmission apparatus (3), between the transmission input shaft (6) and the transmission output shaft (7), maintaining and transferring into an engaged operating state a maximum number of shift elements (A to F) while maintaining and transferring into a disengaged operating state a remaining portion of the shift elements (A to F) with the transmission output shaft (7) being rotatable;
• upon issuing a request for interrupting the power flow, between the transmission input shaft (6) and the transmission output shaft (7) in an operating state of the transmission apparatus (3), disengaging a form-locking shift element (A) in the transmission apparatus (3),
• subsequently engaging the form-locking shift element (A) when a differential speed, in a region of the form locking shift element (A), is within a differential speed range in which the form locking shift element (A) can be engaged by engaging one of the plurality of the shift elements (B to E) after neutralizing the power flow.