Trannie has to come out plus other changes. The 29's are a compromise....should help on the highway at higher speeds for mileage but the engine will have rev a bit more on long grades and the torque converter will slip more at all highway speeds on grades (that will be more pronounced at lower highway speeds like maybe 45-50 mph as a guestimate). Thus more heat in the trannie: I would consider an external trannie cooler if you are going to be cruising up in the hills of western MA, NH and VT.
