Open Diffs - friction modifier

[FlyPenFly]

I have a couple bottles of Redline 75w90 NS which is the type with no friction modifier.

I have emailed Redline and they said it's totally fine to use in open differentials like in my Z4 and Grand Vitara RWD. They said if I so wish, I can add some Friction Modifier so I bought some Lubegard in a tube.

I'm curious though, would adding FM to these open diffs do anything other than make the oil break down faster? Is there any point to adding FM?

 

[demarpaint]

In an open differential I see no point using it at all. Unless you have some laying around you're looking to get rid of, instead of recycling it or passing it along to someone that can actually benefit from it. I wouldn't use it.

 

[LeakySeals]

Lubegard in a tube? what product exactly?

 

[bdcardinal]

Friction modifier is for clutch type limited slip differentials. There is no benefit in adding it to an open differential. It can possibly damage some other types of limited slip differentials that do not call for a modifier like certain Torsen models.

 

[d00df00d]

Originally Posted by bdcardinal
It can possibly damage some other types of limited slip differentials that do not call for a modifier like certain Torsen models.

Interesting. Hadn't heard this before. Do you know how this works?

 

[FlyPenFly]

I imagine that it might make the fluid more "slippery" is what other threads have said. It might also cause the fluid to break down prematurely...

 

[bdcardinal]

Originally Posted by FlyPenFly
I imagine that it might make the fluid more "slippery" is what other threads have said. It might also cause the fluid to break down prematurely...


Yes, some differentials require gears or cones to react in a specific manner and a modifier could change how they act.

 

[Blokey]

Originally Posted by LeakySeals
Lubegard in a tube? what product exactly?


I'm guessing this:

 

[SargeBB]

Detroit by Eaton has a Torsen-type limited-slip and their instructions specifically state to follow vehicle specifications on rear differential lubricant, but that mineral oil, OEM viscosity recommendations, GL-5 with no limited-slip additive is best for maximum benefit.
Tractor Supply and other similiar businesses will have this. However, if you want a name brand, Mobil, Chevron, Phillips and Shell all make a GL-5 that meets the specs perfectly, although you may have to go to an oil supply company to get it.