- Aug 3, 2005
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I have a 1990 Mustang LX 5.0L with the 8.8 rear end. I have to change the gasket in the differential cover, because of a leak. I don't know what gear oil to put back into the differential once I change the gasket. I want to put the Royal Purple 75W-140 synthetic, but I'm not sure if that would be the right oil. Also, do I have to put the friction modifier in the Royal Purple 75W-140 synthetic gear oil? Is 75W-140 the right gear oil?? Or is some other weight gear oil better?????? Any input would be appreciated. Thanks