Had a leak for months now, appeared at first to be the output seal on the transfer case. Removed seal, checked for wear lines and installed new seal twice. I have come to the conclusion the leak is coming from the centre of the output yoke on the transfer case. Is this possible? Oil only shows up on the front U-joint and gets flung all over exhaust from there. Yoke is dry except for the very centre and u-joint... Any ideas?

There is a welch plug in the end of the yoke, that may be your leak.

What the heck is a "welch plug"...

its a plug that has a small hole in the center of it, designed in such a way to allow the componet to breath with out letting contaniments into it. they are found on every driveshaft that has a slip joint.

It is located inside the yoke where the splines are then?
A Driveline shop would have such a plug?
Thanks

It is located inside the yoke where the splines are then?
A Driveline shop would have such a plug?
Thanks
It's part of the slip yoke itself. If you look at the slip yoke behind the u-joint you'll see it. You can try to tighten it up, but chances are your better off to just get a new yoke.