I guess it could be slipping a bit, but I don't think so. The problem is that today people want quiet, smooth cars/trucks, so they design the Auto trans to be so smooth so you can't feel it shift. This causes excesive time between shifts, which causes heat and wears clutch material out faster, beleive me I know this, I did A LOT of research on Auto tranny's when the E4OD went out in my pickup. Also I hate to say it, but Ford designs the Explorer mainly as grocery getters for soccer Mom's. There is no real tough SUV today, most are cars with AWD or 4wd. I think I had the last "real" Sport Utility, the Fullsize Bronco!! Don't get me wrong, I love our X, but I find that I rarely call it a truck, I usually find myself calling it a car, which it really is, an AWD car.