Transmission heat will be your main concern. There are a lot of posts on this and other forums about it. You need to understand how the torque converter works and when it locks in. On my Dodge Cummins if I am in tow haul mode with the shift selector in 2 and keep it above 28 mph the torque converter stays locked and I can pull any grade for any length of time without building heat in the transmission. As soon as the torque converter unlocks the heat starts to build fast. Extended periods of temps above 250 will deteoriate the transmission fluid. Learn how your transmission works and how to keep the heat down.