ls diff oil options

Reply Subscribe

Thread Tools

Search this Thread

Oct 24, 2021 | 03:02 PM

Nilak

Thread Starter

Racer

Joined: Sep 2021

Posts: 360

Likes: 59

ls diff oil options

Hi,
I’m planning to use this 75w90 motul oil for my c4 ‘91 l98 differental:
https://www.motul.com/ro/en/products/gear-300-ls-75w90

other options could be :

https://www.motul.com/ro/en/products/gear-competition-75w140
this one I suppose would protect the gears and clutches well but would cause slightly higher temperatures and would rub some power

or:
https://www.ravenol.de/en/product/getriebeoel/getriebeoele-fur-schaltgetriebe-und-antriebsachsen/ravenol-dgl-sae-75w-85-gl-5-ls
this I think is similar to the first with marginal better fuel economy and power

which one do you think it’s suitable?
I use the car for a weekend driving but also a few trackdays (I usually run 1 power lap and one cooling slow lap)
thank you

Oct 24, 2021 | 04:15 PM

84 4+3

Le Mans Master

Joined: Aug 2017

Posts: 6,928

Likes: 1,486

From: New Jersey

The motul is more than adequate... I'd just reach out about the LS additive. Some companies still want you to add it on some cars while others don't... its a subject people fight over as much as oil but I'm not willing to get into it at the moment. Just question it.

Oct 24, 2021 | 04:27 PM

colter

Burning Brakes

Joined: Jan 2015

Posts: 863

Likes: 74

I put in regular Valvoline 75w-90 gear oil that had limited slip additive. And in parking lots, I'd get some groaning. And so I had ordered some GM limited slip from Amazon, and a couple of clear empty squeeze bottles so I could pull out several ounces, and then squeeze in the limited slip additive.

I stuck with regular oil as I have read some say the synthetic gear oil can eat through the factory RTV. Though some say that's a myth. But I didn't want to take any chances as pulling the batwing would be expensive to have a shop do that to fix a leak.

Oct 24, 2021 | 04:37 PM

Nilak

Thread Starter

Racer

Joined: Sep 2021

Posts: 360

Likes: 59

thanks

the car is not listed by the oil manufacturer, I’ve just chosen it because it has the normal viscosity and it says it already contains LS additive.

Oct 24, 2021 | 04:48 PM

Nilak

Thread Starter

Racer

Joined: Sep 2021

Posts: 360

Likes: 59

is this addictive adequate?

I could only find 4x4 additives in my country

Oct 24, 2021 | 05:32 PM

84 4+3

Le Mans Master

Joined: Aug 2017

Posts: 6,928

Likes: 1,486

From: New Jersey

The slip lock is probably fine. Try it without the additive first. If it needs it then order and add it. You'll get chatter doing low speed turns if it needs it.

Oct 25, 2021 | 09:50 PM

Purple92

Melting Slicks

Joined: Jul 2005

Posts: 2,649

Likes: 863

I run the Red Line 75 - 90 Oil. It supposedly does NOT need the Posi additive.

Oct 27, 2021 | 08:15 AM

Phobos84

Melting Slicks

Joined: Mar 2002

Posts: 2,873

Likes: 764

From: Sligo PA

I put Red Line 75-90 in mine with the little bottle of Red Line LS additive. So far so good. But I probably didn't need the additive being that Red Line claims it already has it in it.