Is yours a manual or automatic?
I had a 91 Sentra with a manual 5 speed that did
the same thing. I disassembled the trans and found
a bad bearing and race. It was a lot easier to do than I thought.
Got the parts at the dealer and
that fixed it. Getting the race out was the hardest part,
I used a Dremmel tool and cut it out. The new one
tapped in pretty easy after freezing it.