I have been experiencing a whirring noise from my 96 Legacy AT, for quite some time now. It started very soft and now is sounding worse like grating gears. The noise comes whenever you are not accelerating. Throw the trans into neutral and still there. Soon as you touch the gas pedal it goes away. I've swerved back and forth trying to determine if its a wheel bearing, and the pitch of the noise does not change not matter which way I turn. When in neutral I rev the engine and no change in the whirring. I'm really getting worried and frustrated. Also I should say I don't think it is the trans, it shifts smoothly, no clunking, and no slipping. Is it possible to be a U-joint in the driveshaft?

 

Any suggestions on which component is going to let out the magic smoke?

Ok I am sorry I was unable to find all the differential whirring posts before I was in a rush. Also I did not do a search for whine.

 

This is just a small update to the problem. My CVs are fine. I did replace the drivers side about 10k miles ago. The whirring had already started by then, but now of course is progressively worse. My diff oil level is good and is still clean looking. Had the car on the car lift and did not note any leaks. Shook and rotated driveshaft. Had some play in it, but I did not think it had too much.