I have a new '13 Power Wagon and noticed after the first 200 miles a strange metallic vibrating type noise which appears to be coming from the rear portion of the pickup. I hear the noise at slower speeds (~35 mph) and rpms (~1250 rpm), and especially right after the transmission has up-shifted. I sometimes notice it more when driving around a curve at those lower speeds. I've read people saying that it could be exhaust related and I'm not sure if it's only found in the 2500 Hemis or not. The sound is definitely not coming from the engine. I really don't think that there is mechanically anything wrong, I am just wondering if the engine is lugging and causing the exhaust components to vibrate more. Any thoughts are appreciated.