Help needed something not right with my new 9 inch diff ?

[ozkiwi]

I just had a brand new 9 inch diff fitted to my truck and it has a drive line vibration since it was fitted so I stuck it on the stands and put it in drive to take this video so someone who knows can tell me what is going on.
At first glance I thought the drive shaft was bent but as I followed the wobble back it is starting back at the pinion yoke or pinion itself.
I paid big money for this diff and before I go back to builder who is supposed to be the guru off diff's I want to know what I am talking about.

Have a look at the video and tell me what you think.

https://www.youtube.com/watch?v=UnhZ...ature=youtu.be