R200 Axle Input Questions

[Gollum]

So, my 280Z has lots of vibration coming from the rear end. Plenty of the common shift clunking, but there's also a steady vibration that starts getting pretty bad at freeway speeds. And when I go over bumps there's loud banging from the rear driveline. I've driven the car in this state for probably a good 20k mi. and it hadn't really gotten worse, but last time I had the car up I couldn't find anything loose or out of place. Front diff mount seemed solid and such.

 

Well a few weeks ago while I was under there I decided to check how much free play there is at the wheels. I know this isn't the most scientific test but I figured it was worth a shot. I was pretty certain the noises were coming from the driver side, not the passenger side. I go to move the wheel and I notice that there's a good 30 degrees OR MORE of free play before you feel the other wheel start to move. I go to the other side and it's like less than 5 degrees of movement, to where it almost feels immediate.

 

So I figure, "Well shoot, I've got a spare R200 sitting around that I know is good, I'll throw that in". But there's the problem. It's a 280ZX turbo diff with the splined press in axles, not the bolt in axles. So here's the big question.

 

Can I convert this R200 over to the bolt in axles using my R200 currently in the car without transferring over the problem?

 

Any help would be appreciated. If the local gurus like John or Jon say just go get another diff, that's fine. I'll just make a run to the local yard sometime soon.

[Gollum]

No responses guys?

 

Well from the looks of things I'm thinking it's too much work when compared to a simple trip to the junkyard in a few months. Then I can hunt around for a ratio I like that's bolt in-compared to having to open up the diff and tearing it apart. Knowing me, first time I open up a diff to rebuild it I'm going to botch it up pretty good. So I'll wait until someday down the road to practice that art.

[NewZed]

I'm not an expert, but I think that, based on the way the diff works, if you have 30 degrees of rotation on one side, you should have 30 degrees on the other side. So that result is a little bit confusing. Are you sure that some of the play isn't being taken up by the u-joints or axle splines? The vibration problem sounds more like a u-joint issue. You can get quite a bit of movement out a bad u-joint.

 

And from what I've read, the side shafts/flanges on both the 280ZX and 280Z R200 diffs should pop out and you should be able to swap them, if the spline count is the same. I've been looking around at various differential options myself so would be interested in what you have there. From what I've been able to figure out, any R-200 diff up to 1983 should be usable with just a side shaft swap, except for 1975 when they used the weird pinion shaft flange bolt arrangement. After 1983 they changed the pinion shaft flange also.

 

I'm interested. My diff is whining and clunky so I'm planning ahead.

Edited January 28, 2011 by NewZed

[Gollum]

The play it certainly not in the half shafts at any point. I thought it was u-joint issues too, but I can't seem to find any signs of play or wear in them.

 

I can FEEL it too, that left wheel moves EASILY in that 30 degrees, feeling then past that you feel the other side engage. Where as on the passenger side there's almost none of that free play feeling. Almost immediately you feel that resistance that then starts turning the other wheel. The problem is certainly in the diff from what I can tell.

 

If the stubs from the 280Z R200 will just press in then I guess that WOULD be an easy swap. Anyone have any ideas if the seals would need to be replaced? They look ok, but they also came off a 280ZXT that had 200k+ miles.

[JMortensen]

I'm not an expert, but I think that, based on the way the diff works, if you have 30 degrees of rotation on one side, you should have 30 degrees on the other side. So that result is a little bit confusing. Are you sure that some of the play isn't being taken up by the u-joints or axle splines? The vibration problem sounds more like a u-joint issue. You can get quite a bit of movement out a bad u-joint.

 

And from what I've read, the side shafts/flanges on both the 280ZX and 280Z R200 diffs should pop out and you should be able to swap them, if the spline count is the same. I've been looking around at various differential options myself so would be interested in what you have there. From what I've been able to figure out, any R-200 diff up to 1983 should be usable with just a side shaft swap, except for 1975 when they used the weird pinion shaft flange bolt arrangement. After 1983 they changed the pinion shaft flange also.

 

I'm interested. My diff is whining and clunky so I'm planning ahead.

This is correct on all counts. What you're saying about one wheel acting differently than the other doesn't make sense, unless you're checking slack between the wheel and the diff. This would basically be checking the splines in the stub axles and companion flanges and the u-joints on the halfshafts and the splines into the carrier in the diff. If you turn one wheel until it CAN'T move, then that would include all the slack in the side gears, splines on opposite side and u-joints, etc.

 

I know people who claim to be able to feel u-joint issues with the shafts installed. I can't I have to take them out to feel a bad u/j. Could also be a driveshaft angle issue. might check that out if you are still stuck.

[Gollum]

Well, sometime this weekend I'll pull the diff and axles to see if I can hunt down the problem at any rate. Just finding the real source will be nice.

[Gollum]

Well I feel like a real doofus now. I guess I was a bit quick with my findings before. It seems like the rear right caliper is sticking just enough that the wheel wouldn't spin with light movement of the opposing side. Somehow I didn't realize that was what was going on the time before. This time when I jacked the car up it was pretty obvious, as it brakes were stuck enough that it was hard to get the right wheel to move by moving the left wheel.

 

So I guess I probably have a bad u-joint. Which is probably better than dealing with a diff issue, but at least I had a spare diff lying around. I'll keep future findings updated here.

[ezzzzzzz]

As a side note, I've always checked halfshaft u-joint play with the tires in a static position. Jack up the car and place tire ramps under the tires (duh). Once lowered back to a static ride height you can check for u-joint play. Like Jon said, U-joint play is difficult to detect (unless it is damn near destroyed). Also check the hardware on the mustache bar. I've experienced the diff nuts backing off and recently found a nut loose on the DS bushing on my newest project. It was causing an awful thumping as the diff twisted the bar up and down.

[Gollum]

While I was rolling my fenders a touch today I pulled off my right side axle to check out the ujoints and they actually seemed fine, though my axles seemed like they were torqued down my a shy third grade girl. Some of them came off by hand!!! That could have been some of my vibration/noise issues. It's too soon to say, but I think some of the highway vibration could have been my wheels being crazy out of balance as they were bald and have been so for a long time. Got new tires on there and bubble balanced them and there's only a small vibration under had accel in 3rd.

 

I'll post more info as it comes.