Mainly looking for good fuel mileage, but have a 5th wheel which weighs 11,000lbs give or take, also my equipment trailer which is 12,000gvw haulin my tractor and some implements.mckey73 said:I guess it depends on what kind of luck you are talking about. There are way better products out there for you. The cummins guys will be along shortly to point you in the right direction. Have you done any mods yet? What do you use the truck for? Or what would you like to acccomplish?