What is this sound?

[dbruesehoff]

Alright, I think I have about a dozen posts going right now so I figure why not one more. Can anyone tell me what this "clacking" sound is all about? Every time is does it the drive shaft jumps ever so slightly. I am guessing something in the trans that might either be going out or out of adjustment. Any thoughts? Is this something serious?


Edit: anyone able to explain how to post a video? I have tried everything including reducing the video size and nothing is working. I think you need to see the video to hear what is going on.