leak at front of driveshaft

I just changed the fluid in the transfer case and now I have a leak at the front of the rear driveshaft right at the u joint, but there is nothing on the outside of the shaft coming out of the transfer case, it is like its coming out the end of the shaft.
Any ideas why this is?

Can you post any pics of it? It would be more helpful to actually see for ourselves what is going one.

Check the vent tube on top. If you overfilled it could be leaking out the vent tube.

//2000CAYukon

I dont think it is the vent tube because there is no leaks on the case itself. There is nothing on the output shaft of the transfer case it looks like it is coming out of the very end of it. I have a good picture of it, but I cant figure out how to post it.

There is a seal where the yoke enter the transmission. If it is leaking onto the drivline, then that is probably your problem. The seal is fairly cheap if I remember right. All you need is a pair of needle nose and a flathead. Easy fix.