As an update - I checked the fluid level and indeed it appears to have been over-filled. As a follow-up to this, I was wondering, in the early morning (even after the car has been driven 10-15 miles) the shifting seems smooth without the somewhat vicious "clunk". I have not attempted to put it under stress or passing gear until I get the fluid to a normal level. My first thought that since it is somewhat cooler in the am thats the reason, but even after the car seems "warmed up" - it shifts smooth. Any thoughts?