i had a similair feeling in my old ae71. It started as a really light vibration and became a horribly loud vibration/sound. It got so bad i pulled over on the side of the road one day to have a look and i noticed that the bolts on the front half of my tailshaft were loose, 1 was gone and the rest were finger tight.
Was lucky the tailshaft didn't drop down and dig into the road and send me onto my roof.
