Re: Wrong Gear Oil?
The Society of Automotive Engineers had different systems for grading viscosity standards between motor oil and gear lubricant products. SAE 50 motor oil is in the same viscosity range as SAE 90 gear lubricant. The API is also part of the current rating system. All are still SAE or ISO rated but the type of lubricant has to be included to tell what the rating is for. Motor oils used ZDDP for tappet protection but gear lubes have extra pressure or EP additives designed for gears for an EP rating in similar fashion as grease products but grease products have there own ratings and extra pressure additive packages so they are all in their own separate categories. ATF & Hydraulic fluid are also in different categories.
The SAE is still used in the US but the International Standard Organization or ISO still takes precedence in the modern era.
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