Cruiser replied:

It may be worth checking the grease nipples. Sometimes they can get blocked/damaged and won't allow the grease into the joint.

skippyking replied:

Guy, it's probably a "path of least resistance" sort of thing. The grease can escape from that link and so only goes there. I would have thought that if there was grease needed in any link in the uni, then that would be filled first before it starts to escape. I doubt you could get grease to escape from all 4 at once because of the least resistance thing. Have you pulled them apart to see if they have sufficient grease in them all? They may well be lubricated quite adequately. On most vehicles that travel at high speed, that I have seen, the drive shafts are quite straight so the uni's don't have to work all that hard. Hope I may have helped. Cheers.