I sealed my diffs wit 2.5mm socket head screws with shoe goo for sealant. they need to be about 3-3.5mm long. no tapping needed they screw right in and no leaks. the epoxy should work but I would be afraid of it coming undone over time, the screws are not coming out unless you want them to. I run heavy grease in my center diff 10,000 in front and 7,000 in rear. works well , but I only use mine for racing, I don't bash.