I have an unlimited with manual transmission and I hear this rattling when I'm getting ready to shift or if the rpms dip a bit. I had a similar sound on a car I had years ago and it ended up being a metal cover that was over the catalytic converter.

Any other 12 owners out there that have the same issue?

 

Yeah but I have an auto. I think it is the exhaust rattling on my EVO skid. It only does it at low RPM's so I think it cause enough vibration to make the rattle.

 

My rattle was coming from a loose rear fender that one of the plastic pins was broke on. On delivery...

 

What he said.

 

I picked mine up today with 6 miles and it has a rattle coming from the back... I think its the top but not really sure