First of all, hello to all from a new guy.
Second.. I have an '06 WRX that I recently bought. I noticed a whining noise coming from the rear of the car. It's very high pitched and fairly faint. I can only hear it when coming to a stop. Sounds to me like it's coming from the rear diff. Is this normal? If not, WTF?! I changed the rear diff fluid, and haven't noticed an improvement.