it increases efficiancy in how the tranny shifts, not how the power is transfered all the time. basically, you may save some fuel in between shifts, due to less "idle time" for the motor while the tranny shifts. i dont drive hard all of the time, and like i said i noticed no gain in town (some hard driving) or on trips (75 mph with the cruise on). i would not expect to gain any noticable mileage with this.