Axle lube friction modifier... All the same?

[Rabbler]

Regarding Limited Slip Differential additives.
Are they all pretty much the same?
Are different types better depending on LSD design? (metal vs organic friction clutch)

I've seen some aftermarket mfgrs (Auburn) recommend the factory Ford and GM additive (by part #) for their units, making me wonder whats so special about their blend?

I remember years ago most friction modifier was this suspicious Blue stuff than stank to high heaven. We used to throw the empty bottles outside in the trash because one bottle inside stunk up the whole shop.
Now all the stuff I run across is clear Amber and doesn't offend the nose at all.
Is it a completely different formula?

The hideous Blue was labeled "severely hydrotreated petroleum" if I remember correctly and I think it was better.

I don't remember experiencing so much clutch chatter back then at low mileage. Especially with metal LSD clutches. eg, Chrysler trac-lok

Comments, Opinions?

Thanks

 

[Whitewolf]

No they are not all the same. LSD FMs vary not only in performance with different materials (for example sinter, paper , carbon) but also in terms of friction durability. The one thing that they do have in common (despite what some people on this board will tell you) is that they all have a negative impact on oxidative stability to some extent. There are some published paper references that I can try to find if you are interested.

 

[PT1]

Originally Posted By: Whitewolf
No they are not all the same. LSD FMs vary not only in performance with different materials (for example sinter, paper , carbon) but also in terms of friction durability. The one thing that they do have in common (despite what some people on this board will tell you) is that they all have a negative impact on oxidative stability to some extent. There are some published paper references that I can try to find if you are interested.


+1 for sure they are all different as are all the differentials.

 

[anti-chatter1]

Rabbler,
I believe the blue FM is the FORD or FORD Racing product.

 

[Rabbler]

So which is better for the different types?

Is the stinky Blue stuff better for a fibre clutch LSD?
Clear Amber for a metal clutch?

I've heard Ford still uses the hideous Blue.
Chrysler uses the Amber stuff now but depending on axle, some have metal and some have fibre clutches.

Does using synthetic or conventional gear lube make a difference as to which additive to use?

 

[unDummy]

Dig the MSDS's for those fluids and compare the ingredients for the answer.
I've seen the same LSD additive used with different clutch material simply by adjusting the 'level' of additive.

 

[Whitewolf]

So please tell us just what is your point?

 

[Rabbler]

Not sure if that last question was directed at me or not.

I think all this talk about MSDS is kind of pointless. It doesn't show the formula of the product just some of the base components and if they are hazardous. I will admit it is kind of nice to know if for example if a chosen additive is 99% mineral spirits. Even if it did tell me more I'm no chemist or tribologist so how would I know which is better?

I guess what I'm asking is if I have a fibre clutch LSD should I use type X additive for best performance and longevity and type Y for a metal style clutch.

Maybe it really doesn't matter...

 

[Whitewolf]

No that was not aimed at you. I was trying to figure out what unDummy was trying to say.
A normal MSDS does not show enough detail to determine anything to any great extent, for the most part the descriptions are generic. An FD MSDS is much more use but most people will never get to see one due to confidentiality issues.
To your question you should use the product that is recommended and at the recommended treat level. The treat rate for suppliment FMs vary according to the concentration of FM in the carrier fluid. An additional but by no means trivial consideration is that they do not all react in the same way with different friction material combinations. So yes it does matter.

 

[SkyPup]

I know the Ford additive seems more effective at reducing LS chatter in my 96 F350 than some of the other brands I tried...

 

[tdi-rick]

In HiPo Ford's and Holden's here with the BTR/Dana rear end, the recommended LSD additive is Sturaco 7098, which may be of interest to you Pontiac GTO and GT8 owners in NA.

 

[byez]

I recently did a fluid exchange out of my Ram through the fill hole, done that twice now. Just trying to clean things up a bit before I drop the cover completely.

Any harm done without using friction modifier in the meantime? Is it true that if synthetic is used, friction modifier is not necessary?

Thanks

 

[Whitewolf]

Originally Posted By: byez
Is it true that if synthetic is used, friction modifier is not necessary? Thanks


No that is not true. You might get away with it depending on the design and materials used but if the system requires FM then you should use it at the recommended treat level