[jmanley]

I just got back last night (4am) from a 2800 mile trip from ND to MT to ID to WY and back again - varying terrain from flat land to mountain passes.

Didn't really seem to matter if I had 87 / 88 / 91 / 92 octane in it, it ran about the same, though on the days I knew I was either offroading and/or going over a pass, I tried to keep higher octane in it merely for a safety factor.

I will say, though, watch your tranny temps! I was pulling a trailer on some days (probably 1.5 ton total weight) over the passes, and even though air temps were as low as 58F, my tranny was hitting 238F !!!!!!

I have the stuff to do the conversion to an external cooler, just ran out of time. BTW - I'm going to write it up as I have figured out a way to do this w/o cutting lines.