Hi
GL-4 gear oils seem to use either Zinc or "sulfur-phosphorous" as the main AW/EP additive. Is there any significant performance difference between these 2 add packs when used in a manual transmission that does not contain hypoid gears? i.e. typical FWD, RWD and some AWD transmissions.
I understand Zinc formulations are less corrosive to yellow metal but most S/P formulations are said to use non-active S/P anyway. I've noticed Zinc seems to be favored in "non EP" commercial applications (Road Ranger etc) and most of these lubes seem to meet GL-4 performance also.
GL-4 gear oils seem to use either Zinc or "sulfur-phosphorous" as the main AW/EP additive. Is there any significant performance difference between these 2 add packs when used in a manual transmission that does not contain hypoid gears? i.e. typical FWD, RWD and some AWD transmissions.
I understand Zinc formulations are less corrosive to yellow metal but most S/P formulations are said to use non-active S/P anyway. I've noticed Zinc seems to be favored in "non EP" commercial applications (Road Ranger etc) and most of these lubes seem to meet GL-4 performance also.
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