That is why the dealer tell us we can haul any trailer we want so we won't buy a different truck. I do feel that this truck with a set of airbags could haul anything just not legally. The duramax has plenty of power, the drivetrain and frame are the same as the 3500. I feel good stopping power with down hill, engine braking and large 4 wheel disc. I believe insurance would be a factor as well, if something where to happen. The truck itself is a beast, it is just the rating game. Most DOT officers check weight and see if your tires are able to handle to load, again insurance and the #'s game