Here is an update, after my second week of 300D ownership.

All the driveline components I've inspected appear to pass. Flex discs look pretty good, center carrier mount is intact (i'm not sure how to assess the bearing, but there isn't much play), CV boots are intact, etc.

I think that the culprit was the slightly shady aftermarket straight pipe exhaust. I noticed that it was off of one of it's little mounting hooks. Once I put it back on, I haven't heard the rapid thunk thunk thunk again. I think it must have gotten a little off line and made some contact with the drive shaft somewhere.

Is there some terrible malfunction that I could be oblivious to? Some monster lurking in the transmission or something? I do have some transmission fluid drips-- my theory is a bad pan gasket and potential bad B2 piston o-ring. Any other thoughts?


Thanks for all the input,
Justin