The Ford V10 performs fine in the mountains of Southern California...Grapevine, Cajon Pass. Let me expand a bit on that: I could tow my previous SouthWind and 3000lb toad over these mountains at 50mph...if I lost momentum I could regain about 45 mph on the real steep grades. However, just because they stick a 5000lb hitch on the RV that does not mean it will perform or be safe with that load. Check the Gross Vehicle Combined Weight Rating, and subtract the actual weight of the motorhome. It will give you a better idea of what can be towed.