Method and system for controlling operation of a transmission lockup clutch

A method of controlling a reduction of an amount of fuel supplied to an engine provided to a motor vehicle with an automatic transmission separated from the engine by a torque converter is provided. The method includes the step of sensing commencement of a deceleration state during which an amount of the fuel supplied to the engine is to be reduced to an amount that is less than an amount of fuel being delivered to the engine immediately prior to the deceleration state. Whether synchronization of an engine output shaft and a transmission input shaft is appropriate under the deceleration stat is also to be determined. Frictional engagement is to be established between mating surfaces in cooperation with the engine output shaft and the transmission input shaft, and a first compressive lockup force is to be established between the mating surfaces during a first time period to urge synchronization of the engine output shaft and the transmission input shaft, wherein the first time period ends before said synchronization is accomplished. A second compressive lockup force is also to be established between the mating surfaces during a second time period after the first time period and before synchronization is achieved, wherein the second compressive lockup force is less than the first lockup force but sufficient to urge synchronization of the engine output shaft and the transmission input shaft.