Apathy

So, I have been hearing a clicking noise from underneath the car since last week. The clicking is high pitched and sounds almost like popcorn popping in a metal pan. So, after jacking up the car I didnt really find anything except the catalytic, the second one, where it attaches to the primary catalytic convertor, is rusted its way loose... Its a little hard to explain, but while the flange type thing is still bolted, the actual pipe seems to have rusted around the weld so that it is a little loose... I can move it with my hand...

Since the clicking noise seems to be coming from underneath the car, right underneath, I was wondering if it could be the exhaust, has this happened to anyone else and what not...

Also, is it possible that the sound could actually be the tranny? When the bearings in a tranny are frigged, how does it sound? How loud does it get?

Any help appreciated...

By the way, car doesnt hesitate and it goes in and out of gear pretty smooth (although the syncros are a little warn)...