My initial post was supposed to be a friendly heads up to the community on ONE of the ways to identify a potential driveshaft failure visually, BEFORE it happens, (as quite a few people have asked what they should be looking for) but it caused a bit of confusion as it wasn’t the commonly seen cv boot tear. I hope this clear things up a bit.
The grease seen was from the driveshaft not, the transfer output shaft. It came from the back cover of the universal joint (see pic) due to a hole, soon to be two holes, made from the inside. If this had gone unnoticed, the driveshaft would ultimately fail.
I hope this helps explain things a little more. There are of course other signs to be aware of. In our case, it’s down to suspension flexing and too much articulation on the joint. We had an opportunity to change it out and so we did. Could it have gone longer? Possibly, but for us, it wasn’t worth the risk with the journey we’re on. 66,000km. No lift. Towing 95% of the time, large majority of our journey is off road.
I deleted the original post to keep things as simple, accurate and helpful as possible.

(This one has more info with pics. Some people don't read all the comments and so I thought this was the best way to do it.)
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