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The chart does not list the GL rating of each oil. Isn't that a very important factor when comparing shear stabilty?



The gear lubes tested in the chart are American Petroleum Institute (API) GL-5, SAE 75W-90 synthetic gear lubes. Samples of API GL-5, SAE 80W-90 petroleum gear lubes were also included for comparative purposes.

The chart is one of many taken from: A Study of Automotive Gear Lubes - pdf. link