Oil is leaking from the differential. I smell it burning when the car is running for more than a few minutes. I just bought the car. I diagnosed it with a mechanic after we drove it and also ran it while up on a rack. It has not been fixed yet.
High pitch whine coming from differential. when I investigated the sound I discovered that the differential had been leaking and was nearly out of oil. I topped off fluid but sound is still there. I do not know what the source of the sound is yet.