I have a 2005 LJ Rubicon with a 6 speed manual transmission. Last summer I installed adjustable control arms, and set them at the same length as my factory control arms were. Earlier this summer I swapped out my 2" springs for some 3" JKS coils. I hadn't noticed any vibes until this week. Driving into town on the Interstate with my wife and kids, I thought I had noticed some vibes. About that same time, my wife commented that she heard a rhythmic vibration. It seemed to come and go about every 2-3 seconds. It only did it at a very specific interstate speed. Tonight I went for a long drive to try and duplicate the sound. At about 78-80 MPH I could just faintly hear something. It was not as noticeable as when I had the Jeep loaded down with the family, but I think I could still hear something very faint if I really listened for it. I do have BFG KM2 MT tires, so they could cause some vibration, but they are prettly low milage tires and I have rotated them regularily, so they are still pretty quiet.
So with all that said. Do I need to adjust my pinion angles. Or is this a normal harmonic vibration that is not cause for concern.
So with all that said. Do I need to adjust my pinion angles. Or is this a normal harmonic vibration that is not cause for concern.