A method of operating a transmission device. At least one of the shift elements is a form-locking shift element. A sensor is associated with the form-locking shift element which can determine an operating state of the form-locking shift element. When a request to disengage the form-locking shift element occurs, a disengagement control signal is generated and the form-locking shift element is actuated in the direction of disengagement, depending on the disengagement control signal. The transmission device is transferred to a safe operating state in which the transmission output shaft can rotate, when an actuating pressure that changes the operating state of the form-locking shift element is determined with the sensor, even though a disengagement control signal was not generated, and/or when the sensor is associated with at least two form-locking shift elements and the form-locking shift elements are subjected to actuating pressure to implement a requested operating state change.