OK, my trans went out at 109,00 miles
Another auto owner told me his failed at 85,000 miles.
Hard to tell about how long a transmission will last. This is similar to people making claims about how long an OEM clutch would last. I have heard folks posting their OEM clutch died in less than 30K miles others have had it for some 80K to 100+K miles.
It all depends on how hard you drive the clutch or the transmission which most folks don't mention it in their post or may not know based on previous owners' use. For example, I have a 98 OEM clutch with 60K miles and I started tracking my car when it had 2000 miles; have 100+ track days the last 10+ tracks and 15K miles are with a CTSC. According to some, my clutch should have been toast by now. Sure it is not like new but it it still holding up. My point, do your homework regarding how the transmission was used. YMMV.
But if you are looking for a used automatic transmission, here is a post:
http://www.nsxprime.com/forums/showthread.php?t=142982