Don't forget to drain both the transmisison and the OD. They are interconnected and use the same oil. The former has an obvious drain plug at the bottom, the latter requires removing the rectangular plate on the bottom with the six (or is it eight?) bolts. Generally you can reuse the gasket if you are careful. (Be careful, those gaskets are hard to find.) Clean the screen in there while you have it off.And when you refull, make sure the car is level.