There's a plug under the diff. That's where you let the oil out. The filling plug is on the end of the box next to the wheel. It's the bottom plug furthest from the front of the car. I think it's bigger than the rest. This is where you put the oil in. When the oil runs back out of this hole, it's full. There is a step inside this hole, so make sure that you puch the filling pipe in far enough, or the oil will start to come out almost immediately.