et2, we just came through Colorado going over the Vail pass. We do go slow as we weigh just over 40,000 lbs. with our 425 Cummins. We did slow to 30 on the steepest part of the hill which is a long, long, climb. It is just over 10,000 ft. above sea level.
Our engine temp will go up but not too much as the computer will control the engine and transmission. Our temps went up to about 210-215 for the engine and trans as our normal is 197 for the engine and about 203 for the trans. We just sat back and enjoyed the view (beautiful) but I could hear the radiator fan roaring when we drove next to a higher guard wall.
MM.