Attached is an image of my rear prop shaft of my Grand.
As you can see it seems to be spraying some form of oil. This has been going on for many years (yes many) but now seems to have worsen.

I can not figure out where the oil is coming from as it seems to be "seeping" out of the joint some how. It does not run along the slip yoke outside as that's dry, unless some one can explain the workings of such a shaft. Is the slip hollow?

I'm confused.

Also I have yet to see anything in my research where a WJ has that disc thingy too. All others have a simple uni-joint

Thanks

Shaft.jpg