Procedure for operating decelerating downshifts with the participation of a form-locking shift element of an automatic transmission comprising a torque converter lockup clutch

A method of carrying out coasting downshifts that involve an interlocking shifting element in an automatic transmission which comprises a torque converter lockup clutch, at a beginning of the coasting downshift, positive action is taken on torque, the method comprising the steps of:

• at the beginning of the coasting downshift, either fully or partially disengaging the torque converter lockup clutch for either fully or partially decoupling a drive-train from a drive aggregate, and
• carrying out this action upon the torque such that an engine rotational speed only falls below a turbine rotational speed once a synchronous point, for the interlocking shifting element, is reached.

A method of carrying out coasting downshifts that involve an interlocking shifting element in an automatic transmission comprising a torque converter lockup clutch, the method comprising the steps of:

• at a beginning of the coasting downshift, either partially or fully decoupling a drive aggregate from a drivetrain by either partially or fully disengaging the torque converter lockup clutch;
• and
• carrying out the partial or full decoupling of the drive aggregate from the drivetrain such that an engine rotational speed only falls below a turbine rotational speed once a synchronous point in the interlocking shifting element is reached.