Method of detecting and preventing tie-up during a double transition up-shift

摘要

A method of detecting and preventing tie-up during a double transition shift of an automatically shiftable transmission operatively connected with an engine is provided. The method includes. A) shifting the automatically shiftable transmission from an initial speed ratio to an intermediate speed ratio; B) commanding the automatically shiftable transmission to shift from the intermediate speed ratio to a final speed ratio; D) determining if the automatically shiftable transmission has been operating in the intermediate speed ratio for greater than a predetermined amount of time after commanding the automatically shiftable transmission to shift from the intermediate speed ratio to the final speed ratio; and E) preventing shifting from the intermediate speed ratio to the final speed ratio to avoid tie-up if it is determined that the automatically shiftable transmission has been operating in the intermediate speed ratio for greater than a predetermined amount of time.