A method for operation of a drive train having a drive machine and an automatic, unsynchronized gearwheel variable-speed transmission, which can be connected to the drive machine by using an automatic clutch is described. A control device carries out a selection process as a function of vehicle parameters and/or operating variables of the motor vehicle to determine whether a gear change of the unsynchronized gearwheel variable-speed transmission will be carried out with the clutch engaged or disengaged. To ensure reliable operation of the motor vehicle, a gear change is carried out with the clutch disengaged in a time interval after initial starting up of the drive train and/or after starting of the drive machine and/or when a malfunction is identified in a component in the drive train.