I don’t know about the more experienced members but I just replaced the gasket on my differential cover and it still leaked! Prior owner didn’t even have a gasket- just some gasket material. I took the cover off, and applied some gasket adhesive to the cover side of the gasket and it sealed it up. I use 3M Yellow Super Weatherstrip and Gasket Adhesive. I also had to replace all my bolts as they were stripped at the threads to torque properly (I think it’s 30-50 foot pounds


1951 GMC with positive ground. Engine is a ‘54 Chevy passenger car (Serial Number 0024472F54Z) with a ‘56 head (casting code on top of head 3836848 GM 4), Casting Code (on passenger side on side of head B56 848 850)