Drive Growling Loudly

[shrew]

97 2800 SCR with a Bravo III. I repowered 2 seasons ago, upgrading from a 454 (7.4) to a 496 (8.1) MPI. I just came off of a week's vacation. I noticed the drive has been sounding a bit louder than normal over the past few weeks, but towards the end of this past vacation it has gotten significantly louder. Since non of you can 'hear' the noise I'm making as I try to imitate the sounds while I type, I'll try to do my best to describe it. As stated in the title, it is 'growling' for lack of a better term. Not a grind or a squeel, but more like giant dice being rattled in a giant plactic cup. It only occurs when I put it into gear, and does it regardless of the engine RPM's. It does it in both FWD and REV. and doesn't seem to get any worse when I turn the drive from side to side. However, that is relative, since I'm not sure it could get any worse.

My fear is I'm going to need to replace the drive. Anyone have any thoughts?