I’ve got a 2000 Avalon with 177500 miles on it, and it makes a high pitched whining noise only at 30-45 mph when I’m pressing on the accelerator. I’m assuming since there’s no sound when I’m coasting at those speeds it isn’t a wheel bearing. Transmission fluid and filter has been changed (made the sound before I changed it). Once Im at 50 mph+ it’s completely gone. Alternator was load tested at autozone and they said it fine, not sure how good their machines are though. Battery and terminals replaced (oem) as well. Could it be a failing relay squealing for help?
Can you get some video of the noise and share it here? You can post video links right in the text window.
Check your belts to see if anything could be rubbing. And I've seen cases where idler pulleys can make this kind of noise to. and hit us a video if you check that simple stuff and it's still happening.
Thank you very much Jacksonishere, I was skeptical about the alternator bearing and after seeing you’re comment and replacing it the sound went right away.