transmission whine under load. 00 9-3 SE

[900Aero]

My SE is running better than it ever has after my Indy did some nice tuning. It has 174k and feels brand new.

I was taking my duaghter to college 1000 miles away when I noticed and hum or whine under load at highway speeds. The load could barely touching the gas or hard acceleration. Although, I will say the whine diminished briefly under hard acceleration.

When the car was slowing down in gear, like coming down a hill, the whine was there but it was not constant. It would change pitch in a regular rhythm, lower-higher, lower-higher. The whine under load was a constant pitch.

Any ideas? I'm thinking clutch release bearing or some bearing in the transmission. Also, any ideas on how emergent (or not) this could be.

TIA

JD

[900Aero]

My Indy has dx it as the bearing on the output shaft. He said it could make that noise for years before it needs to be replaced. He said I'd know when it needed to be replaced when I heard the noise in 1st or 2nd gear. Right now it's only 5th gear on the highway when I hear it.