I have a 2008 ram 1500 quad cab short bed with 5.7l engine. I recently purchased a 26' travel trailer, 5000 lbs, 6000 packed and rolling. On flat roads and hills, all is good, but once I reach a steep incline, even on highways, the transmission down shifts a lot. I have the tow /haul mode on. I've towed smaller popup trailers, 3000 lbs, Off Road, no problem. I'm not even close to the towing capacity, something just doesn't SEEM right. Is this typical with this truck. It's mainly a lawn ornament, pick up a load of wood, help family move, it only has 36,000 miles on it. Any help would be great.