I have a 2001 2500 HO 6-speed with the 3.54 gears. I tow a 34' Keystone triple slide which averages about 12,500 lbs. I have added an Edge EZ for some towing performance. All I can say about the rig is..WOW! It pulls like a dream. I towed the 5'er from NEPA to South Fl this winter I81, I77, I26, I95. Didn't take ot out of OD the whole trip excent when stopping, even northbound on I77 through Fancy Gap (over the Blue Ridge Mountains) Rig sits level and very stable on the open road even when passed out by 18 wheelers flying.