I pulled a 13000 lb kz sportmen toy hauler with a 98 2500 chevy 350 with 410 rearend ran around 3000 to 3500 rpm every where it surprisengly towed preety well did that for 6 years even took it it to jacksonville florida from st.louis ran around 5000 rpm up mont eagle at abou t 50 mph and the check engine light cam on about a hundred miles later whent off exhaust just got that hot did the same thing on the way home other than that trip whent great but i`m glad i finally got my ram 3500 cab chassis cummins manual dont even know the trailers back there now