Is the GL norm an indication of EP or AW pack??

[kilou]

Hi,

I'd like to know if the API-GL rating of gearbox oils is an indication of the extreme pressure (EP) additive pack only or the antiwear (AW) additive pack.....or both? In short 2 GL5 should have the same EP capabilities but do they also have the same AW properties?? Is there anything to look at to know the "strength" of the AW pack of a manual gearbox oil?

Thanks

 

[Pablo]

Not necessarily within a GL "rating". Depending on the chemistry two GL-5's could have very different AW characteristics (and actually EP as well).

 

[kilou]

Of course they can use different EP or AW additives but if they have the GL5 rating, it means they both achieve the same level of protection, at least in term of EP additive....otherwise the GL rating would be meaningless no? Now would they also achieve the same level of protection regarding anti-wear properties (although they may use different sorts of AW additives)?

 

[Pablo]

The rating is a minimum descriptive specification. The performance portion is in ASTM. I don't think there are chemical limitations in either direction, other than the ability to meet the performance.

Try this: http://www.api.org/certifications/engineoil/pubs/upload/1560.pdf

 

[kilou]

Thanks for this