Hi this literally just happened to me with my 2008 tribeca. i was driving along and then clunk car completely stopped with all lights on.
the dealer told me bring it in we may have to reset the computer. so i drove it. they had it for about 40 minutes then came out and told me they'd been seeing transmission problems with the tribecas and they will need to replace the transmission that they'll probably have it for over a week!
wow. we've had the car less than a year.