Broken Tranny part
You can get a new driveshaft made to eliminate the ball/ trunnion if you ever have trouble with it
like here:
www.forwardlook.net/forums/forums/get-attachment.asp?action=view&attachmentid=95454
As long as the ball trunnion "works fine" they are OK. The rub comes in rebuilding them. Parts are expensive, and you must get the pressed in center pin centered correctly. If the outer housing is worn, they REALLY become expensive.