Help R200 variations

[jeffball610]

I finally got off my ass and ordered my new driveshaft to mate my Toyota R154 to my Nissan R200 diff in my 4G63 Datsun 510. Sadly, it doesn't bolt up. The rear companion flange has a larger bolt pattern on the shaft than on my diff. I could swear all Z31 R200 diffs were the same, but are they truly? Does anyone have good information about this topic so that I and others can be more well informed?

 

Disclaimer: none of the following pics are my own.

 

This is showing the variation of rear diffs people might swap in. I have a Z31 R200 (not pictured) but it has the companion flange that is square like the 280Z unit pictured here.

 

This is showing my issue. I have the square flanged unit and my shaft has the larger bolt pattern for the round flange. However, most of the information I'm finding shows the square flange to be a 280Z unit which has bolt on axles at the diff. I have slide in axles and it's from a Z31. Information seems to be slim on this topic.

 

This diagram shows a square flange and it's on a Z31.

 

The only information that somewhat helps me to identify my whole setup is a sketchy eBay posting. The post says it fits 240Z, 260Z, and 280Z but also states the unit is from a Z31 300ZX. It also identifies the unit as an open diff from an automatic unit. Here's the only pic that shows the same unit I have.

 

What makes this more difficult for myself is that I picked these parts up almost 10 years ago and I can't be positive which cars they were pulled from. I didn't have any issues with my axles, diff, and rear hubs, but they are a little easier to identify. Looking at them, they seem to be from later year Z31 units since they have 4 bolt axle flanges. The square type diff companion flange might be an earlier year setup as it seems to be more like a 280Z unit. This is all very confusing and unnecessarily complex. Does anyone have good info on these diffs?

 

I'll need to check with my driveshaft shop and make sure that I gave them the proper driveshaft for reference. If not, then I'm paying to have a new flange put on. But at least I'll have a driveshaft and be one step closer to driving my car.

[Lockleaf]

Could you simply swap that flange out to one that matched your driveshaft?

[datzenmike]

The Z31 were all R200 but came in 2 and 4 pinion and clutch and viscous LSD

 

2 pinion open '84 and up VG30E & VG30ET

4 pinion open '87 and up VG30ET

4 pinion CLSD '88 and up GL & GLL VG30ET

4 pinion VLSD 'Jan '88 and up SS 5 speed VG30ET

[jeffball610]

The Z31 were all R200 but came in 2 and 4 pinion and clutch and viscous LSD

 

2 pinion open '84 and up VG30E & VG30ET

4 pinion open '87 and up VG30ET

4 pinion CLSD '88 and up GL & GLL VG30ET

4 pinion VLSD 'Jan '88 and up SS 5 speed VG30ET

That's good info. Is there anyway to tell the difference from the outside or if these were laying on the ground? I'm pretty sure there's a stamping on the case that tells the diff ratio, but is there any other info we can find without taking the rear cover off? If I remember correctly, some of the later turbo models came with finned covers. That might help to distinguish different models.

[datzenmike]

The cases are not stamped with the ratio. If in the car refer to the engine tag. Look in the lower right corner for RC35 (3.545 ratio) or RC37 (3.70)

 

The most definitive way to know what you are getting is to drain and pop the rear cover off. The ratio is stamped on the outward facing edge of the ring gear. 37/10 is 3.70 and 39/11 is 3.545 You may be able to find and read it with a flashlight through the oil fill hole. With the cover off you can check for open or one of the two LSD types.

[jeffball610]

Here are the stampings on my outer case. This is an old pic and I'll try to get better ones when/if I pull it. Maybe "83" refers to the year of manufacture?

 

[datzenmike]

The cases are cast in huge numbers and you can't just throw them away when '84 rolls around. It's likely some code or mold revision number by the manufacturer. Hitachi? by the looks of it.

[Stoffregen Motorsports]

Casting numbers offer very different information from stamped numbers.

 

I've seen some diffs come with stickers on the cover identifying the ratio and carrier.

 

The best way to ID it is to pop the cover off.

 

If flanges are interchangeable, don't use that to identify the diff. What if the previous owner swapped the flange? Obviously if it came out of the car it was born in, this doesn't apply.

[jeffball610]

I'm gathering lots of good info (at least for me). If I were to swap the companion flange instead of fixing the driveshaft, what is the torque spec and do I need to replace a "crush sleeve" or the like when doing this? The diagram I provided has some torque numbers, but not the specifications i.e. ft/lbs in/lbs nm etc. It looks like maybe 19-30 ft/lbs, but that seems weak for a part like that.

 

*Edit* Now I'm reading  somewhere else it's between 100-140 ft/lbs. Sounds more like it, but still not specific. And of course those numbers don't match what I'm looking at above, but that doesn't make it right either. :/

[datzenmike]

In theory if there is a crush sleeve it should be replaced, but all you are doing is loosening the pinion nut and then tightening it again. (well with a different flange) Bearing clearances and pre load has already been worked out and this does not really change.

 

The tightening torque for the pinion nut on an R 200 A from a D21 Hardbody (it's all I have) is 100 to 200 ft lbs. Yours is likely similar. I would suggest removing the nut and tapping on the rear side of the flange with a socket to move it forward. I have switched flanges on an H-190 differential by doing just this. Took 30-50 taps but perhaps preferable to a gear puller disturbing the pinion? My aim was to swap the flange with as little disturbance to the pinion as possible.

[jeffball610]

In theory if there is a crush sleeve it should be replaced, but all you are doing is loosening the pinion nut and then tightening it again. (well with a different flange) Bearing clearances and pre load has already been worked out and this does not really change.

 

The tightening torque for the pinion nut on an R 200 A from a D21 Hardbody (it's all I have) is 100 to 200 ft lbs. Yours is likely similar. I would suggest removing the nut and tapping on the rear side of the flange with a socket to move it forward. I have switched flanges on an H-190 differential by doing just this. Took 30-50 taps but perhaps preferable to a gear puller disturbing the pinion? My aim was to swap the flange with as little disturbance to the pinion as possible.

I have a gear puller to do this with. This is likely the route I will go. It seems the simplest and least expensive. From other swaps I've seen, I will need to cut off part of the round flange to fit it through the crossmember.

 

Oics forthcoming. I pulled the cover today just to take a look since I had the rear out to redo my brake lines. It's stamped as a 39.11 (3.545 ratio) and is a 4 spider open diff. That doesn't seem to match the info provided and is what is confusing me. It seems to have parts from several model years. The 3.545 open should come from the 84-86 Turbo, but according to the listed info, should only be a 2 pinion unit. I guess this is why we check things instead of going off of listed information, even if it's from the OEM. Who knows who put what parts where over the past 30 years.

[datzenmike]

What makes this more difficult for myself is that I picked these parts up almost 10 years ago and I can't be positive which cars they were pulled from.

Thought you said you didn't know what it was from. Now you say it should have been 2 pinion and from an '84-'86 turbo?

 

So, if you have if an open diff and a 4 pinion (4 spider gear) my info says '87 VG30 Turbo. Additionally it's listed as 3.545 (automatic) and 3.70 (standard) It is what it is.

[jeffball610]

I guess I received some bad info. The only thing I could find for a 3.545 ratio was the 84-86 Turbo open and you previously stated they only came in 2 pinion. This is why it gets confusing for me. There is no need for Nissan to switch ratios and other parts mid cycle. I hate when OEMs do that. My 03 350Z has a rev 1 transmission that they found to have an issue with synchros and changed it mid year in 04. Then they changed the motor for 05 and again in 07 (I think). Don't get me started on all of my 4G63 facts. In any case, my 510 has so many parts from so many cars with various cycle changes. I'm trying to document it all so I, and any future owners or people wishing to do this swap, have the best info they can.

[jeffball610]

Here's what I discovered. The 84 (and possibly up to 86) cars came with the smaller square front flange. I assume this is left over from the 280Z and ZX R200 units. My particular unit is from an 84 Z31 Turbo automatic. I have replaced the flange with a unit I pulled from a 86 Z31 non turbo automatic. The fit is the same, but the fillet on the splined in was slightly larger on the 86 unit. I don't think this will make any difference, as it was a very minor change. Sorry, no pics of that part.

 

I don't think these numbers mean anything, but I thought I would include them. This is from the top of the unit.

Stamping on the ring gear.

4 spider unit

Round flange on. Torqued to 130 ft/lbs. (I couldn't seem to find an exact number)

Bad picture of the old unit.

I don't know if any of this will help anyone else, but I thought I would post it for future reference.

[510T]

Hi Jeff,

 

I just wanted to point out that the diff above is a 2 spider unit.  The two gears on the shaft are the spiders, the other two are the side gears.  A 4 pinion diff would have parts that look something like this:

 

 

I have nothing else to add except that I am glad your project is moving forward again. :D