Originally Posted By: Greasymechtech
Claims not the same as validation? GL4 obsolete testing apparatus still used? or are they all blending from memory?
The GL-4 rating has been discussed many times and proper explanations have been given.
You obviously don't understand gear lubes and testing. Once again, GL-4 is a protection/service rating for gear lubes.
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API Category GL-4 designates the type of service characteristic of spiral-bevel and hypoid gears in automotive axles operated under moderate speeds and loads. These oils may be used in selected manual transmission and transaxle applications.
This type of service rating implies a certain level and type of additive mix to achieve that level of protection of that service rating.
There are ASTM and CEC tests using the FZG and other machines that can test fluids equal to and above what the GL-4 specs require.
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I have no issue with Redline's claims.
I do since claims are not the same as validation.
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The commercial additive suppliers have validated the PI packages for GL-4 service when used with specific base oils.
The important thing to consider here is differences between the PI packages and base oils for ATF's versus dedicated MTLs.
The PI package and base oil for ATF's start out with very low (some may say, "very thin") viscosity oils and use additive components for wet clutch applications. The PI package for an ATF has less than 18% of the Anti-Wear (AW) chemistry found in MTLs.
The PI package and base oil for MTL's start out with higher viscosity base oils, use additive components targeted for synchronizer assembly applications, and have about 5.5 times more AW chemistry than do ATFs.