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NC280z

R200 LSD Sanity Check

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I do appreciate all the input you've provided. I'm wondering if the type of oil I used to fill the diff would affect the clutches. I'm using Pennzoil 75-90, which was labeled as good to use with GM posi diffs and I'm not certain if this would affect the performance of the CLSD in my diff. 

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Is it a clutch LSD?

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It is, and I know that Positractions aren't all clutch-type but I'm assuming that the generic term refers to clutch LSDs?

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Won't effect it to the point you are describing.....

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It is, and I know that Positractions aren't all clutch-type but I'm assuming that the generic term refers to clutch LSDs?

 

So you have it apart? CLSD clutch LSDs us clutches and discs that are spring loaded. They can be 'dialed in' for the grip and how much they can hold before being forced to slip.

 

VLSD or viscous LSDs use fluid friction. Very much like the clutch fan on our Datsuns.

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I was mostly wondering if the "friction modifier" in gear oil for LSDs helped keep the clutch plates engaged, but most of what I've read is that the modifier actually helps them slip so that they dont' wear too quickly.

 

Would a worn LSD cause a loss in power, or would it just act like an open diff? 

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Open. Speaking of open did you check yours yet?

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Friction modifier isn't to help wear.

Its so that the LSD doesn't chatter when going around tight corners.

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I had considered that also, but all the information I've seen is pointing to a clutch-type. VLSD's in R200 longnoses are exceedingly rare, save for those few from the late z31 turbo cars. It looks like Whitehead Performance sells and rebuilds the stock Nissan clutch LSDs, so maybe they have the repair kits available.

The later ('88-) Z31 had both CLSD and VLSD long nose R-200s with the turbo cars. The '90 and up S13 240sx also had long nose CLSDs available.

 

 

I almost can't believe Calif. Datsun didn't check the turning of the diff. Or maybe they did.

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Popped the cover off of the diff, here's what I've got. 

 

dNl6sWP.jpg

 

It doesn't look like many of the R200 LSD photos I've come across in Google searches. Anyone have an idea of what it might be from?

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The outer edge of the ring. What numbers are stamped on it?

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37:10 AL 6 11 24

 

There's no crosspin in the spider gears so I'm certain this is an lsd. I haven't pulled the carrier out yet to check it

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dNl6sWP.jpg

 

Not seeing much room for any clutch discs and plates.

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So maybe this is a VLSD unit? Would that explain the lack of coupling strength at low speeds (like hand-turning the driveshaft)? 

 

p5GQ88c.jpg

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Thanks for the link! If it were open the wheels should spin in opposite directions when the driveshaft is spun, right? Because this unit turns the wheels in the same direction when turning the driveshaft. Strange thing is that if I turn a half-shaft in one direction, the other half-shaft turns in the opposite direction. 

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No. Assuming equal drag if you spin the DS the wheels should spin the same.

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Or one will spin more (up to 100% of the input ratio)

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Well, it looks like California Datsun sold an open diff and passed it for a CLSD. Time to contact them and see about a refund.

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Well, it looks like California Datsun sold an open diff and passed it for a CLSD. Time to contact them and see about a refund.

 

We wish you the best of luck.  Al is a scammer at heart.  He doesn't frequent here because he's been so "unfairly" "maligned".

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I've seen open diffs that both wheels turned together in the same direction when the pinion is turned, but if you held one still the other would spin easily. 

If you turn a wheel on an open diff while holding the pinion still, the other side will spin the reverse.

A clutch LSD the wheels are physically locked and turn together in the same direction. I doubt if anyone is strong enough to overcome the breakaway setting and to hold a CLSD wheel while the other spins.

Viscous LSDs are fluid coupled and (I assume) 'softer' in their engagement, could be turned opposite directions at low speeds?

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His response

 

Thank you for the information. We have a 30 day warranty or exchange policy. Since its been several months there is no longer any remaining warranty. We are resellers of these parts and there is no way for us to test a differential. The supplier we purchased this from is out of the county for a few weeks. I will see what he says, however since its been so long there is no way to verify this information, but I will try. Sorry about that.

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His response

 

Thank you for the information. We have a 30 day warranty or exchange policy. Since its been several months there is no longer any remaining warranty. We are resellers of these parts and there is no way for us to test a differential. The supplier we purchased this from is out of the county for a few weeks. I will see what he says, however since its been so long there is no way to verify this information, but I will try. Sorry about that.

 

This is terrible...

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I asked who the vendor was, "That's none of your business, why did it take you so long to figure out it wasn't a lsd?". Classic deflect and also convenient the vendor is gone. I'm getting ebay involved

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