Bummer. Post up a video here and we'll help you diagnose it.
I'll take one when i get home. We were starting to assume it was the starter coming out and knocking the flywheel but this is definitely sounding like its up around cylinder #1 and sounds like whacking a steel can with a stick.
Odd thing about it is, no power loose, gas mileage is normal, oil isnt glittery, no smoke, smooth idle, smooth transitions from 8 to 4 mode and back. The noise gets worse and more frequent when its cold out, but its never started it from a start.
So this morning, got in it for work like normal, it started making some clicking like it does but it got quieter. Realized i forgot something at home, turned around, parked in my driveway, which has a minimal slope. Grabbed my stuff, tossed it in and went to get t he trash can, but said I'll start it so i can just jump in and go, started it and damn!! tink tink tink tink ...wel thats not good, i moved it to level ground and it still was making it so i decided to park it up and borrow a vehicle. Luckily neighbor is a mechanic and has a heated garage w/ 2 post lift and it sounds like he's going to have some time to help tear into it this weekend. but still ******. Nice thing is that Texas Speed has the DoD deletes in stock and a good price, was 670 with the 6.2 cam...because ya know..i might as well get SOMETHING outta this while its apart.