I did a search found some somewhat useful info and some that actually might relate, but I wan't some confirmation before I go further. When I first put my car into gear ('04 STI, if you couldn't guess) and I let the clutch out I sometimes hear a thunk\knock in the rear of the car. I believe it's too far back to be part of the trans, I'm thinking it the Rear Diff maybe, or perhaps center Diff. Sounds like it's off to the right of the car, but being as I'm sitting on the left you can't take my word for it. In one of the posts I read it said that STI have this problem and Scoobie doesn't know what causes it. Does this sound like the same thing? Could it be a Ujoint in the rear diff with a bad seal? Any help would be greatly appreciated. Being that I've only had this car for a few weeks it would be kind of discouraging if the dealer sold me a car with a bad rear diff.