Nissan recommends 75w140 oil for their 2way clutch type LSD.

I did some research & found a bunch of people who said they switched to redline 75w90 combined with redline's diff friction modifier. Those who did said it quieted the diff down a lot.

I'm wondering why that is.

If a different weight oil minimizes the amount of chatter does it mean it's making the clutch plates slip against each other more easily & therefore is making the diff less effective with less bite? So in other words it's actually a bad thing?

Or am I seeing this wrong?

Your thoughts please?

Thanks

-e

Not real sure. That's definately a JMortenson question.

After we installed my LSD into the 70, I used NAPA 75w90 and 8oz of friction Modifier and it's quiet with plenty of grab. I haven't felt or heard it slip yet.

Dave

8 oz. of friction modifier might be a bit much. Most LSD's I have experience with call for 1-2 oz.

1 or 2 oz of which type? Some come in bigger or smaller tubes or bottles. My impression is that the amount of "active ingredient" is the same in each. Use one container per diff, and then if it still chatters, add another. That's the way I do it. On some really tight American LSD's I've had customers use 3 bottles.

Regular 80W-90 works fine IME. If you want "special" oil, I like SWEPCO 201. You don't need additive with SWEPCO on a lighter LSD, you might have to add a bottle for a tighter one.

As to the chatter itself, think of it this way: The diff doesn't need to chatter to limit the slip. If you test breakaway with a torque wrench and no additive, you'll get higher readings before the LSD "breaks loose" but if you have the additive you'll have a consistent reading. If you want the LSD tighter, shim it tighter. No reason to live with the chatter. It is pretty annoying.

Oh ok I get it now

Thanks for the explanations...

The current trends in CLSD oil is towards higher viscosity numbers. OS Giken sells a 80W-250 that works very, very well in all my customer cars running OSG Super Locks.

But it too has some kind of friction modifier already mixed in with the oil right?

I'll add some friction modifier to the 75w140 oil I got & see how I get on. Thanks all!