Method and system for controlling a vehicle propulsion system based upon an adjusted clutch torque capacity

A vehicle propulsion system includes a transmission having manually selectable gear ratios, a manually operable clutch for selectively connecting the transmission to an engine for receiving torque from the engine and transmitting that torque through the transmission for propelling the vehicle, a clutch position sensor that generates a clutch position signal and a controller that is programmed to receive the clutch position signal, determine an actual engine output torque, determine an actual clutch torque capacity value based upon the actual engine output torque and the clutch position signal, determine a difference between the actual clutch torque capacity value and a clutch torque capacity from a torque to position table corresponding to the clutch position signal, determine an adjusted clutch torque capacity based upon the determined difference, and control an operation of the engine based upon the adjusted clutch torque capacity.