I have only had this truck for a month and have not had the chance to tow our 8000 lb loaded fifth wheel camper. I used to tow it with a 6.0 gasser and was really a struggle on some hills and I was curious how well the duramax was going to do. The 3500 is 100 percent stock. Just from driving the truck around I don't think that I am going to have any problems. Any imput would be appreciated.