I'm getting an oscillating vibration thats sets in around 50mph, with a period of about 1s. It fades around 60mph. Vibration was before these items so you can discount them as the suspects (lengenthend and balanced drive shafts, LI/LO hubs, 35/12.5 tires BFG Mud, rebuilt rear end with eaton posi, 4.56 gears, new axles, bearing etc, new tranny, new 383). I asked the drive shaft people about angle induced vibration and was informed that drive line angle vibration would be prevelent from 10mph to infinity, so they didn't think I had and issue with angle. The vibration will smooth instantly when you decelerate. Any comments? Thanks.