kfink

Any way to test to rule out the alternator bearing?

thanks to all for your comments. the sound does get louder/quieter depending on road speed. From reading the posts I think the differential fluid replacement is a good place to start. More questions, is the yellow dipstick under the airfilter box is the refill for the front differential? Where do you refill AT fluid?

No change while turning, not a wheel bearing. ATF was a little low, I added half quart to top it off. There are 230K miles on the car.

In the last few weeks I've heard a whirring noise in my 01 outback while accelerating. When I take my foot off the gas, the noise nearly disappears. While accelerating, it gets louder the faster I go and is constant. Any ideas??