On a steep uphill pull in the summertime, set the throttle wide open in whatever gear it takes to pull the hill at walking speed or so, then climb out on the running board to steer and get away from the heat inside the cab. I've seen pictures of big rigs pulling the Grapevine Hill in California that way.
Jerry
An excellent time to put the spigot to use as well, draining spent coffee. On the 250 HP, 88,000# GVW semis I started on, there was no shortage of opportunities to get out. Sometimes you could walk faster than the truck was going..
