Auto Trans Whine

[eeore39648]

I drive a 2000 Frontier daily. It has 212,000 miles on it and has no problems. It has been serviced by the book, all its life. It uses no oil, nor does it burn it. Still gets the same MPG as it always has.But it has developed a, Whine, that seems to be coming from the trans.I have replaced the alternator, still whines.I have taken each belt off idividually, still whines.I changed the trans. fluid and filter, it still whines.It whines when your in park or nuetral when you rev the engine.I seem to here it more when its first driven, the whine lessens after driving, but returns after sitting a couple of hours.What should be done? Should I drive it til it dies?