Driveshaft rattle?

[pit viper]

The car has a rattle in the driveshaft whenever I accelerate. This is the first non-FWD car I've owned, so I figured I should check it out. I crawled under the car, and checked the shaft at the rear diff. Everything seems tight.
Then I crawled up front, and where the driveshaft attaches to the tranny, it wiggles a little and makes a nice metal-on-metal clanking. Also, there is some front-to-back movement of the shaft, and though I'm not sure if it's supposed to do that or not.

If I'm not mistaken, there should be a joint where the shaft hooks up to the tranny, correct? Is it replaceable seperately, or do I need to get a new shaft? Any other thoughts on what it might be, or do I seem on the money?

[lodit]

It might be a similar issue like my 2001 A6 4.2.
I'm getting a fluttering noise at low speed when I press on the pedal.
Only a momentary flutter, then acceleration works as normal, but it's annoying.

I have no idea what is causing it, nor does the dealer that I've asked to inspect it on numerous occasions.

Hopefully, someone on here knows about it and can help with its remedy.

Cheers,

Steve

[2.slowT]

I know the seals do go bad and its not that big of a deal. I need a rear seal. Dont think you need a whole new shaft though unless there is something really funky going on.