Odd vibration from drive train

I've been hunting a vibration for months now not wheel bearings as I originally thought as it only hummed at speeds over 35. Today I put my car on the lift with it in gear trying to find it and seems to be coming from the center of the drive shaft while under the car. It's a hum that sounds like a drive train issue, it's nearly deafening in the car any body deal with this or know what it could be? All help is appreciated.