Don't use a torque wrench. My differential rear cover plate cracked when I performed the diff fluid change a few months back. If you look at the 1/2 inch drain plug it doesn't have a head and body like the oil drain plug. It's one continuous screw so if you try to torque it, it will just keep spinning until the plate cracks or until it screws itself into the diff.
I felt like an idiot after realizing this fact.