The plugs usually have a fiber washer on them, and you use a gear oil pump that screws onto a quart bottle to pump the oil up through the drive until it starts ta run out of the vent hole. Then pull the pump hose out and screw the plug in, then replace the vent plug. I bought my oil pump on a bottle of marine oil ( Penzoil) from Wal-mart for around 8 bucks.
