I had to slog through that today pulling a gross weight of 76,500lb. My cooling system was nonplussed but did the job. Right around the VA/WV line, I was starting to pick up enough heat that I thought I might have to pull over - the fan on/off cycling wasn't keeping up, but it started to level off. AC was a champ though, my vent thermometer never climbed more than 5*.
On the downside, I got just north of 5.5mpg from Nitro, WV, to Raphine, Va, a 220 mile trip which took 4 hours almost on the dot.
__________________
|