On steep grades, heat is a major problem for truck systems. Hot tires wear prematurely, hot engines can overheat and become damaged, and hot brakes are not as effective. Managing the heat of different vehicle systems becomes an important part of a trucker’s job when driving hills.
If you use your engine brake and engine fan override switch effectively and are careful about your speed, engine and brake heat can be managed. It might mean driving slower on hotter days, but you can never be too careful when it comes to your safety and protecting the vehicle.
However, one part of the vehicle is difficult to keep cool: the drive axle differentials. Unlike the transmission, these gear boxes normally do not have any type of cooling system and if they overheat, there is nothing to do but park and let them slowly cool down. When driving up and down hills, make sure you pay attention to your differential temperature gauges as well as your engine and transmission temperatures.