trans fail safe....please help!!!

[bdriven]

Hello folks,
I know there's a lot of threads about this issue, but none seem to quite fully agree on something, so I thought I'd swing it by you all.......my X5 has about 135k miles on it, no complaints, love the car. my tranny went bad, so I had it rebuilt. Now, on the road, shifts smoothly, rides like a charm. then I hit the first steep uphill....dead, went into trans fail safe. only reverse works, slips on drive. turn off the car, turn it back on, rides nice again. in summary, goes into trans fail safe, when you try to go from 0-60, or when a good up-hill comes along.
Craving for input! Thanks a bunch!!!