Rattle inside driveshaft

i think that is from one of the things the workers at chry.did to drive the dealers crazy back in the 70s they had allot of different things like this happen wen they didn't get there raises they wanted i never herd of this thou.i have herd of extra bolts in rear ends or letting bolts lose in motors and rears all kinds of different thing maybe some one else can tell you more.