Vibration gone, so too my tailshaft????

Gotta be a connection there somehow. All bits from other cars of mine come together in latest beast June 89 Brumby ( should call her June) and get this horrid vibration so swapped in another known single piece tail shaft and same crap so pulled it and bunged up the output and made a bracket to keep it there. Vibration gone. Next trick is to follow my Subaru Gurus advice and check the alignment of drivetrain