I have had a vibration that starts a about 60mph and gets worse as I go faster. It has lasted through the rear tires being replaced and as of late has got much worse to the point that it needs to be fixed. I checked for play in my u-joints and have none, but the center bearing I can move quite a bit. Is it supposed to move around in the rubber or is it supposed to be held firmly in place? I haven't put much effort into figuring this out yet but after doing a search it seems there has been a lot of problems with this bearing, and I would like to have some sort of standard to compare mine to before I spend hours and money on something that isn't bad.