Hi all; I have a 2006 Ram 2500 with a 5.9, I6, auto trans, 4x4, truck has 139K miles. Mods are; smarty Junior tuner, air dog fuel pump, air intake, no lift, no big tires, tires are new (approx 10K miles on them) recently balanced and rotated. I am having a bad vibration issue when under power, as soon as you let off the gas, the vibration goes away. It starts at around 30 MPH and gets bad at 50 MPH, tends to level off a little at 60 MPH but I am also letting off the gas a little. You realy feel it going up hill at 50 MPH, felt in the steering wheel and gas pedal and the entire truck vibrates. Transmission is new with approx. 38K miles on it, rebuilt using Georend parts (troque converter, valve body, etc.). After test drive, mechanic ruled out transmission and U-joints. Anyone have any ideas?