I was assured it worked, from a very reputable shop in a good area known for working on BMWs, got the trans for much cheaper then most I have seen though. If it turns out to be an internal failure I will surely contact them. I definitely agree on a roll of the dice with a used trans, but for the price vs time to rip into mine and fix it I just wanted a quick in and out swap. The plan was to rebuild the original and have it ready to swap back in if there was a failure or find another X5 with a bad trans and pick it up to swap in. The good news though is now at least if I have to take it back out again I can have it done in less then a day.