Hey everyone, I'm new here and need some help. I bought a 04' 2500 HD. It has the 5.9 w/ 325 HP. It has a quadzilla chip, mbrp exhaust. It was 2 tone paint, and when we took the running boards off, found alot of rust so had all new wheel arches put on, new rockers and cab corners. I had the truck painted all black, with black chip guard. Bought a new set of 17'' wheels, 285/70 w/ nice All Terrain tires. Had the tires balanced and rotated two days' ago. Right before I had them rotated I started noticing a vibration and thought it was from the rear somewheres. After the roation, it went away or so I thought. Last night and today I started noticing it again. It seems like its when I'm going 40 + MPH and it only does it when my foot is BARELY on the throttle. I mean it wont do it if I'm giving it just a touch more than hardly anything. If I just hardly barely push on the pedal while I'm going I can feel it. Anyone have any ideas what might be going on?