OldGuard

I have a 2001 convertible that has a rattle noise coming from the rear end of the propeller tube or from the torque converter area. I thought the rattle was coming from the front end of the propeller tube but after getting it up on the lift it sounds like it is coming from the rear of the propeller tube area. I was told the only way to be sure where the rattle is coming from is to drop the propeller tube. I have had this rattle about 3 years now and it does not seem to effect anything, it is just annoying to hear.
The rattle is louder when the car is in drive then when it is when park, and the rattle will go away if I'm in drive and step on the brake and add a little gas putting a slight strain on the drive train.
Has anyone ever had or know of anyone who has a problem like this.
I do not have any idea what it costs to drop the propeller tube but according to my service manual there is a lot of work involved. Has anyone ever had this done ? If so what kind of price am I looking at? I think when they build this car they started with the propeller tube and built the rest of the car around it.
Any info will be helpful, thanks