GL4+ and GL4/GL5 gear oils instead of GL3

[inquirer]

Are GL4+ and GL4/GL5 gear oils really forbidden for a car with a transaxle that requires a GL3 oil according to the manufacturer? I was thinking of TOTAL TRANSMISSION GEAR 8 which is listed as a GL4 in Total's website, but I think as GL4+ on the bottle.

On the other hand MOTUL MOTYLGEAR which is a GL4/GL5 oil, and the one suggested by Motul for my car, says:

Quote:
Suitable for any type of seal and yellow material used in gearboxes design.

So what should I do? Avoid them or not?

 

[Badroberts]

You don't want to use GL-5 rated products in applications where yellow metals are present. The extra sulfur required for GL-5 EP performance is corrosive to them.

I find it a little odd that Motul claims GL-4 and GL-5 performance on the same product. My understanding was that the specs were mutually exclusive.

 

[inquirer]

Originally Posted By: Badroberts
You don't want to use GL-5 rated products in applications where yellow metals are present. The extra sulfur required for GL-5 EP performance is corrosive to them.

I find it a little odd that Motul claims GL-4 and GL-5 performance on the same product. My understanding was that the specs were mutually exclusive.


Was researching the topic myself. Here is a video from a guy that talks about GL5 oils: https://www.youtube.com/watch?v=Z7NpsMZ9pBQ
He says he has never seen a gearbox affected by them.

Anyway, Motylgear is a semisynthetic oil and I suspect that Total may be too. I'm thinking of Red Line MTL which I think is a fully synthetic one.

As for Motul's claims, Motul is a well respected company, a big name in the field of motor oils. Do you think they would make false claims?

 

[TinyVoices]

I'm not big on the gl5 hurts a gl4 transmission deal but in my own experience gl4 specific fluids in a gl4 transmission shift better than gl5 fluids in the same transmissions, boutique brands or not.

 

[zeng]

Originally Posted By: Badroberts
You don't want to use GL-5 rated products in applications where yellow metals are present. The extra sulfur required for GL-5 EP performance is corrosive to them.
Really ??
Do be mindful ,today is 2018.

Quote:
I find it a little odd that Motul claims GL-4 and GL-5 performance on the same product. My understanding was that the specs were mutually exclusive.
Invalid claim.

 

[inquirer]

Originally Posted By: TinyVoices
I'm not big on the gl5 hurts a gl4 transmission deal but in my own experience gl4 specific fluids in a gl4 transmission shift better than gl5 fluids in the same transmissions, boutique brands or not.


If you watch the video (I have shared the link in a post above) that's what the guy also claims. The production of new GL4 oils has increased competition between companies and they produce higher quality formulas, at least that's what the guy says.

 

[supercity]

GL-4+ is not an official API category. GL-5 and GL-4 can be met with the same formulation.
ASTM D130 for GL-4 is not all that strict, I think it's a 3a or 3b. Modern GL-5s beat that easy so there is no real guarantee one is safer than the other. GL-4 can also be formulated with typical Sulphur/Phosphorous EP additive or non-sulphur based AW additive. The latter would be fine even in a GL-1 application. I would look for a GL-4 that is also recommended where GL-3, engine oil or straight mineral oil is recommended.

 

[zeng]

D130 requirements of GL4(obsolete specs) vs GL5 vs MT-1 :

Do note GL4 1 hour test duration as against GL5 3 hours test duration.
Most modern day GL5 achieves D130 1a,1b or 2.

 

[zeng]

Originally Posted By: TinyVoices
I'm not big on the gl5 hurts a gl4 transmission deal but in my own experience gl4 specific fluids in a gl4 transmission shift better than gl5 fluids in the same transmissions, boutique brands or not.

+1.

Purely from the perspectives of gear shifting (comfort), a GL4 carries Friction Modifiers to achieve desired ratio of static/dynamic Coefficients of Friction (which was never part of GL4/GL5 specification requirements ) , and it's not about components protection.

Hence, a product that claims GL4/GL5 or GL4+ as provided by OP above, typically carries a Friction Modifiers providing the intended ratio of static/dynamic COF's.

Thus, it would be suitable in an application calling for GL4 for shift comfort, and probably higher level of components protection at similar viscosity gradings.