Quite frankly, I always start my trips in the evening hours for many reasons. The obvious one, less traffic and wide open roads and with both of us being in the greater Southern Calif area, thats an important aspect and maybe not so important to others in a more rural area.
I like to take care of my diesel and there's no doubt that those grades we're speaking of are hard on any engine/motor, gas or diesel. I dont have the 3126 but Im still at 350 hp in my 3176(10.3 litre) and with my MH being 17 years old, pulling a toad and loaded to the hilt, Im still down to 3rd gear keeping my RPM up going up that grade outside of Bishop(or at least some portions of that grade). Last year, mistakenly, I did the Kingsbury grade out of Minden, Nv into Lake Tahoe, talk about a hill! I wont do that one again anytime soon. To me, its a fact of life in So Cal during the summer months....your arent going anyplace without hitting some heat and Id just as soon take it a tad easier with cooler temps in the PM/early AM hours. Its just something I do and everyone is different. Anyways, if your in or around Tahoe after July 7th, we'll be at Tahoe Valley for a couple of weeks...stop by and say Hi! :B