Patent ID: 8463482
Filing Date: 2013-06-11
Classification: F16H

Abstract:
1. A method for predicting via a controller the health of an automatic transmission having at least one torque transmitting device with a calibrated air volume and a calibrated number of friction faces, the method comprising: determining a free running clearance of the at least one torque transmitting device; determining a free running clearance per face of the at least one torque transmitting device; determining if said free running clearance per face is greater than a calibrated free running clearance per friction face for failure of the at least one torque transmitting device; determining if a shift has converged; determining a total number of completed converged shifts when said shift has converged; determining if said total number of completed converged shifts is greater than a threshold number of completed converged shifts; determining an initial clutch volume if said total number of completed converged shifts is greater than said threshold number of completed converged shifts; determining an initial free running clearance of the at least one torque transmitting device; determining a change in free running clearance per face of the at least one torque transmitting device; determining if said change in free running clearance per face is greater than a calibrated change in free running clearance per friction face of the at least one torque transmitting device for failure; and activating a service indicator configured to signal that transmission service is required in response to at least one of said free running clearance per face being greater than said calibrated free running clearance per friction face for failure and said change in free running clearance per face being greater than said calibrated change in free running clearance per friction face for failure.