To start, I've got a k2500 suburban w/7.4, 4l80e. I've had 33's on it for years (65k miles or so) w/3.73 gears runs little under 2000rpm @70 in OD). Towing (4-6K pounds very rarely, no probs with overdrive, unless I'm towing my 30' camper trailer), daily driver, family road trip stuff etc. I do...