1/2 Shaft

Have you tried tightening the collar? It looks like you are just leaking a little grease past the seal. My half shafts were so severely over greased that they were seeping grease out between the welds at the other end.

The part you show is a sliding joint that moves in and out as necessary. The small shaft has a male spline about 6" long and the tube has a female spline to match. If you take it apart to look at it, do not change orientation of the splines when you put it back together. You will get severe vibration if the orientation is wrong.

Jim is correct. I'll add that if a u-joint catastrophically fails, the shaft disconnects & extends on the splines but does not fly apart, even when smacking the ZF cases hard enough to crack them (inboard u-joint) or tearing the inner fender panel apart (outer u-joint). FWIW, I'd be more worried if NO grease showed, as the splines must have grease in order for the halfshaft to move in & out and the rear suspension to work correctly.

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Originally posted by jack deryke:
Jim is correct. I'll add that if a u-joint catastrophically fails, the shaft disconnects & extends on the splines but does not fly apart, even when smacking the ZF cases hard enough to crack them (inboard u-joint) or tearing the inner fender panel apart (outer u-joint). FWIW, I'd be more worried if NO grease showed, as the splines must have grease in order for the halfshaft to move in & out and the rear suspension to work correctly.

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Thanks guys. I was able to tighten it somewhat by hand, about 1/8 inch movement when I turned it. So maybe this is all it needed. I was just getting worried because it was slinging some grease around and I thought the seal (if there is one in that location) may be in need of rebuild. The U joint areas have a very slight movement when I tug up & down on them, which is why I may consider a rebuild anyway. About a year ago the other side was seeping some grease at the U jounts when moving them up and down, so this side may be due a reubild soon anyway. I hear it is hell when one of these break lose.

Hell indeed. I've seen maybe a dozen very expensive ZF cases cracked like a walnut from a loose halfshaft flailing around, and a few more with the whole inner fender panel destroyed. This last is also bad 'cause theres a brake line 2" away that also gets ripped apart..... Check your u-joints for incipent failure by carefully looking at all the bearing caps. If theres a shiny polished ring showing under the snap-ring, that means the cap is moving in the yoke. And movement only happens when the u-joint needle bearings are beginning to fail. This's one reason why I don't like grease shields or those pretty li'l DeTomaso logo-thingys that get glued in above the u-joint caps. Makes such inspections difficult-to-impossible.

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Originally posted by jack deryke:
Hell indeed. I've seen maybe a dozen very expensive ZF cases cracked like a walnut from a loose halfshaft flailing around, and a few more with the whole inner fender panel destroyed. This last is also bad 'cause theres a brake line 2" away that also gets ripped apart..... Check your u-joints for incipent failure by carefully looking at all the bearing caps. If theres a shiny polished ring showing under the snap-ring, that means the cap is moving in the yoke. And movement only happens when the u-joint needle bearings are beginning to fail. This's one reason why I don't like grease shields or those pretty li'l DeTomaso logo-thingys that get glued in above the u-joint caps. Makes such inspections difficult-to-impossible.

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Jack, I remember years ago when you posted issues about the importance of checking the 1/2 shafts. I have been doing a visual inspection of the u-jount caps with the snap ring "in place" (because you can see a small portion of the cap where the snap ring does not totally meet). Is that the usual practice for inspection, or is the actual snap ring removed to view the cap? I usually also rock the car with car in gear and look to see if there is any movement of the u-joint cap area.

When I had my one 1/2 shaft rebuilt about a year ago, the caps looked ok on visual inspection (no shiny area near the snap ring space), but when I grabed a hold of the shaft and shook it, the damn thing moved about 1/4 to 1/2 inch, and grease came out of the "inside" of the u-joint cap area, and so it wasn't holding grease too well. So I had it rebuilt right away.

The shiny ring will be visible 'cause the snap-ring or e-ring normally has a wider end, sometimes with a hole in it, and when the cap rotates, the ring will be as wide as the widest part of the snap-ring. As you found out, just because no ring shows does not mean things are peachy-keen in your u-joints. But if the IS a shiny ring showing, you definitely got problems. Having someone partly engage the clutch while you watch each u-joint in turn for too much motion is also a good way to check for wear.