Here are my experiences and thoughts. I don't place much value on the manual as it is probably written for the majority of uses for the E-450. Being much heavier, I consider a MH much different. I engage T/H when driving in cities where there is a lot of stop and go or I am exiting a freeway and need to slow down. On straight aways, I disengage it. I do use T/H going up and down mountain areas. I do have a problem on some long, steep downhills where a slight press of the break brings the MH to a too low of a gear. If I see this as a potential, I take it our of T/H and downshift manually. Any thoughts or comments are welcome.