RTV, what a PIA!!!! It's all sealed and doesn't leak so Im happy.

 

I'm rather old school. Gaskets are rather cheap and easy to use. I put RTV on the cover side only. That allows me to remove the cover for service without replacing the gasket. I keep new gaskets just in case I happen to tear one taking the cover off.

As an aside before I started doing my own again, someone used black RTV-it leaked. On another truck they used orange RTV. It didn't leak, but I had to pry the cover off. They now make RTV special for differentials. I know folks use this RTV all the time, but I'm not a fan. The right gasket trumps the DA factor every time.