I agree, constant downshifting is bad and causes heat. Our electronic controlled transmissions don't "hunt" like the old vacuum controlled trannies did. But they will downshift on every uphill if the rear end gear is tall enough. This won't hurt anything and the lower rpm helps mileage on the flats. If you don't want to hear it downshift on every uphill, then by all means, gear it low enough that it's already running high enough rpm that it doesn't need to downshift. Like running in direct drive all the time. Going from 3.55 to 4.56 will put you at close to the same rpm with the 3.55 in direct or the 4.56 in O/D. Lock out O/D with the 3.55 (unless it's an '05) and you'll have the same effect. No downshifting because it's already running 2400~rpm at 70mph. And stay out of the city. It shifts constantly in city traffic regardless of gear ratio.2k2_AtlanticBlu said:Constant downshifting is bad because it causes heat in the tranny, and that will wear it out much faster, it also kills gas mileage. Gears will really help with the problem.