I towed my 79 F150 home, on a homemade, all steel, car hauler (about 3500lbs), with the truck, (somewhere around 5000), plus a bed fullof crap in the truck (enough to squat it almost tothe bumpstops), so im guessing somewhere around 10,000lbs. The rear suspension was begging for mercy (coils were MAXED), but i pulled it out of O/D and it really towed it good, it was stable, stopped it good, and had plenty of go power, except up some steep hills, i had ti floored and tachin 4500 to keep 50, but for the most part 55 wasnt a problem, thats with a 5.4L and 3.73s with an E4OD trans.