U-Joint Oddity???? Never seen this......

  I was under the car yesterday looking around, in prep for journey to Phoenix, and noticed really dusty grease zerks on halfshaft u-joints.   Figured grease would be a good thing.....unknown as to last time......      Connected up easily to one of the zerks and after about two pumps, I noticed grease coming out of the backside of the u-joint???????????

Thought this was rather odd, and after scraping around in there with a long screwdriver to get the grease out, I discovered some sort of a hex fitting installed in place, with a 3/16" or so piece sticking out of the hex fitting....that moved in and out a bit......

Has anyone seen this in their halfshafts before?????

Are these some sort of a anti-too much grease device for u-joints?????

Similar results on the rest of the u-joints, about 1-2 pumps with grease exiting  this piece, excepting last one....but figure two pumps is grease in......better than none.

Never seen anything like this, figured I'd check and see if this was normal for some app's or something that a vendor came up with to keep grease out of the engine compartment?


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