Hard shifting at altitude

[patagrande]

We just got back from a trip to the Sierra, and at about 6,500 feet I noticed that the tranny shifted harder than at sea level, especially from 1-2 and when when passing. Why is this?

Next week we are taking a trip to about 10,000 feet, and I wonder if this kind of shifting puts strain and wear on the tranny.

BTW, my off-the-line accelleration was terrible, with lots of smoke; upper-end was okay.

The good news: no noticable oil loss on a 1,000 mile drive, and I got about 30 mpg on the freeway!