Driveline vibration

[Neil Patterson]

I wonder if there is anyone out there who could help me with an intermittant vibration and low sound that occurs at highway speed. It comes and goes with no apparent steering or acceleration or decelleration motion. I suspected the u-joints in the drive shaft however they seem ok by trying to move the drive shafts. You can feel it under you're feet in the cab so I also thought hanger bearing however it seems ok. Could it be cv joints or wheel bearings with no transfer of vibration to the steering wheel ? I am going back to the u-joints and maby take them all off and replace them as I have almost 200,000 K on the 99, 2500 Silverado ext cab long box. TKS Neil