I have 3 items that might be handy.First, I recommend against using Teflon tape for this application because if any small bits get loose off the plug, they may migrate to seals or bearings and wipe them out. Second, use a black iron plug and not galvanized, as this will keep the zinc from leaching out/off (especially on the typically found "import" sourced plumbing fittings that we are blessed with nowdays. Thirdly, I've had great success with synthetic gear lube (specifically Amsoil 75-90W)when I changed the diff lube when I got the car. Especially on the wagons, with their 4.56 gears, all that jazz is thrashing around a bunch in there. Great for cold and hot weather.