2004 Ford F-150 Drive train bracket in the rear

Noises problem
2004 Ford F150 V8 Two Wheel Drive Automatic

Ahh, where to start. About 3.5 weeks ago, I noticed that there was a noise comming from the back of the truck. I thought something was at the nose of the bed rattling around. Unfortunatley I was wrong. Every time I pull in/out of a drive way or over a speed bump it makes that noise (sounds like somethings is being stressed or twisted? With no lub) It is not from the back of the truck or so I think. Last night I was walking out to my truck (I parked in different part of my drive way) and saw a puddle of something. Some type of oil? I crawled undernieth and it looks like it is comming out of the (universal joint?) Bracket that holds the drive train to the rear wheels. I am unsure, but, I think that bracket is cracked because when I ran my fingers over it bare metal showed instead of the coated metal (like the rest of the peice) Do you think I could replace that peice and be ok? Or do you think that I need to take it to a dealer to have it done properly. What else could be wrong to cause that. I am not rough on that pick up I just drive to and from work. Judging by my normal parking place it has been leaking for a while and I just never noticed.