I got a driveshaft out of a '91 Diesel overdrive 2wd. There is something loose in it that goes clunk. It doesn't rattle, but it's something that slides and clunks when I turn over the driveshaft like a rainstick.
Is this some kind of internal balancer? I assumed that's what it was, but the driveshaft shop and junkyard guy both said that they'd never seen anything like it before.