Please forgive me if my terminology is a bit off, I'm posting this as I uncover this problem, and my FSM was foolishly wiped with the rest of my computers memory.

 

I took my Z on a drive today, but didn't get far until I heard some evil coming from the rear end. It turns out that my passenger side half shaft (I can never remember if they are technically CV or half shafts) has dislodged itself quite a bit from where it seats in to the differential.

 

I pulled it out. There appears to be no damage, but the question remains... How did this happen? Is there supposed to be some sort of circlip at the end of the spline assembly, in the notched groove?

 

I've never removed the spline from the differential, however about a year or so ago I replaced the half shafts with some that had less miles on them. I thought the original ones were clicking, but it turns out that noise was from the rear brake pad pins not being installed properly. I still have my original half shafts.

 

Thanks in advance for any input.

 

The car is a stock 1980 ZX. R180.

 

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Sorry, forgot pictures.

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I've tapped the spline assembly back into the differential until it is flush with the casing. I will Re install the original half shaft, test drive, and Re inspect.

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I don't know what it is called either but it is basically spring ring that holds the shafts in the diff. That spring ring might have worn to the point that it is not holding as well as it should or it might have cracked in two and fallen to the bottom. Those spring rings are still available from Nissan, at least they were two yrs ago,  I would pull both halfshafts and investigate and replace both rings.

Thanks. I'll do it. I drove the car for about 20 miles just now and Re checked the shaft. It appears to be holding in place, but without the spring rings, it sounds prudent to pull them both and find the rings.

 

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I think that it's called a "circlip".  Circular clip.  If you didn't seat the clip in the groove the last time that you installed the half-shafts (that's what we tend to call the u-joint "drive " shafts [which is what Nissan called them back then] then the axle might have been loose and worked it's way out.  Or, as grannyknot said maybe it's just worn out.  Usually it takes some serious effort to remove the axle from its clip.  I use an oiled chisel face myself to wedge it out.  They should be very tight.  The clip is in the diff.

Reptoid,  I had the diff out of the car at the time for reconditioning and to have a limited slip unit installed. I took the diff and all the new parts to a Differential shop and I remember the mechanic telling me had a hell of a time installing the new circlips because the spring action on them is so strong.  So just be aware that this might not be a job that can be done with the diff installed in the car.

I will proceed with caution. Thanks for the fore warning. I have a spare differential, with the same issue,, passenger side is out, drivers side is in there tight. It's from an '82, and the splines are shorter than the '80 differential. I'm not sure I can use it, but I can use it to see how bad the circlips are to install.

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Nissan does still show them available 38225-N3100 Side Gear Circlip $2.54 each.

Finding the old ones or pieces thereof might be more of a challenge.

The clips are the same for all the R180's

 

I wonder if I can find or make a sort of flexible shaft with a magnet at the end to send into the drain hole and sides with the shafts removed.

Realistically however, I'm sure ill be removing it completely from the car and pulling the rear cover on the bench. That rubber bushing at the rear of the differential is worn anyway.

I drove it, after hammering it lightly back into place and it does remain in place, but I'll bet money if I went and pulled hard it would come right back out.

I appreciate the replies.

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2 hours ago, Reptoid Overlords said:

I have a spare differential, with the same issue,, passenger side is out, drivers side is in there tight. It's from an '82, and the splines are shorter than the '80 differential.

Edit - the R200's are.  Maybe the R180's aren't.    The diff axles are different length, left to right side.  If you had two short ones in your diff, one of them won't lock in.  Shouldn't be any difference in axle length by year.

Looks like you have spare parts.  Maybe you got some mixed up.

Edited February 24, 20196 yr by Zed Head

1 hour ago, Zed Head said:

  Maybe you got some mixed up.

This is quite possible.  At the time of removing and replacing the half-shafts, I recall marking a "D" and "P" to distinguish between driver and passenger side, which still exist to this day.  However, that doesn't mean that they didn't get mixed up before I marked them.  I have a beer drinking buffoon of a friend who was present that day.  Although I wont rule out the possibility that I just spaced out and installed the wrong side half-shaft.  Just to recap the current configuration:  I now have the original half shafts installed in their original position.  The half shafts that I installed a last summer are  on the workbench, and are the same length.  The original half-shaft "telescopes" or extends further than the newer half-shaft, the one i pulled out last night. 

Maybe the half shafts i used to replace the original ones were the same length, and wrong in the first place, in other words, two left side shafts. 

This all makes quite a bit more sense now, as I look at the spare differential on the floor.  I can see how the casing is not asymmetrical requiring one shaft to be longer than the other.  Just to be specific, I'm talking about the half-shaft, not the spline/axle that should require a great amount of force to remove. 

The half shafts are identical. No size or length difference in any model S30