It is the prop shaft going into the transfer case. This has been confirmed by SRT engineering and I have a replacement on it's way.
Since I kinda dropped in on this conversation; I have a 2014 SRT that is about a week old and was just in for service to address this issue over the past 2 days. Ironically, they just received a new SRT Jeep in today and it has the same problem. They are ordering 2 prop shafts