My brother and I just hauled a 1959 Chevy Fleetside home with a 18 ft trailer and towed it with a 2004 GMC extended cab 3/4 ton with the Duramax Deisel and Allison transmission. What a setup! That GMC never broke a sweat. The transmission breaking worked great in the tow mode. We pulled 70 to 75 mph all the way. That truck didn't even slow down 1 mph going up hills. It is one heck of a truck.
