Resolution - 2012 SRT8 Grinding/Popping Sensation
It ended up being a universal joint. They replaced the front transfer case. The vehicle feels a little different, but the primary problem is resolved.
I was very impressed with the Jeep dealership in Tuscaloosa, AL (Locklear). This is the first time that I've done business with them, and they went out of their way to make sure I was satisfied (loaner car, exceptional communication, etc.).
Interestingly, the service manager noted that another JC with AWD came in a couple of days after mine with the same problem. Because of their experience with my rig, they were able to fix the other vehicle quickly.
If a mod would be so kind, pls transfer this thread to the troubleshooting thread.... Tks!