Thread: Transmission Whine Troubleshooting PLEASE HELP

I have a '01 Grand Prix GTP w/ 93k miles on it.

Starting at about 20-25 MPH through highway speeds, I get a loud low-pitched whine. The noise appears to come from the front-center of the car. This whine is most pronounced when decelerating, but exists accelerating and keeping speed as well. I put the car in neutral on the highway, and the whine did continue, even though the car wasn't in gear. I also tested it directly in 2 and 3, as well as D. (In 1, I couldn't hear it over the sound of the engine, since I'm at ~4.5k RPMs by that point.) I also noticed that the pitch seems to vary slightly by vehicle speed. It is also louder when turning right, and much softer when turning left.

I replaced both front wheel bearings & hubs about a year ago, so I don't think it's the wheel bearings.
Any advice on what might be the cause of this issue? I'd appreciate any troubleshooting help. Thanks!

Sounds like your left front wheel bearing is going out. Did you install a new bearing or was it a used one? I havent seen any new bearings with anything less than a 1 year warranty so you should be able to get a new one under warrant. I have seen them fail with only a few months on them and when these cars were new they came back very often to the dealership under warranty for wheel bearing noise. Sometimes you get lucky and they last a long time but more often than not they just dont last very long and there are a lot of cheap aftermarket ones that dont last.