I have the shakes and need some help

[bumpsburb]

Well, I don’t but my 87 burb does. In the last 6 months the carrier bearing has gone bad three times. When I get up to highway speeds the vibration is loud and comes from behind the front seat. I can place my hand on the rear floor and feel the vibrations. Not to mention the loud noise coming from the back of the burb. Any ideas as to what is wrong? It has been in the shop for a week and at first they said the rear end was bad but when I asked why the carrier bearing is going bad they couldn't answer that. Tomorrow they are going to place some sort of indicator on it to see what is out of round. Any ideas or suggestions are appreciated.

Thanks in advance.