You don't really need any sealant, but some Grey RTV for the drain plug isn't a bad idea.
The drain plug basically uses a 1/2" (12.7mm) drive socket wrench. It is a square drive with 13mm sides to the square but the 1/2" drive works quit well over and over again.
The fill/check plug is freakin' crazy. It is
not a 3/8" (9.525mm) square drive like most people think. It is a 10mm square hole. Usually a 3/8" square socket drive wrench will work, but quickly that will ruin the hole because it is slightly too large. Some people like to wrap the 3/8" drive in a strip of aluminum from a cut up soda can to make up the difference. Others like me got sick of that and bought this:
NISsport 10mm Gearbox Fill Plug Tool
But it seems to be discontinued. =(