I'm repairing an oil leak and am replacing the seals (and some other parts, but this is an o-ring thread). I also bought a new oil pump. The pump came with the gasket that goes to the block, the oil sump gasket and an o-ring. I can't find where the o-ring goes. It is about 5/8" to 3/4" in diameter and less than 1/16" in thickness. Any one know where this goes? My factory shop manual didn't show it either. Thanks.