just pump the old fluid out, and take it off, all you need to do is, remove the belts, alternator, flop it to the side, unbolt the snout and slide it off. get new fluid, and some of that sealant for the s/c,(i forget the name of it) i used high heat rtv, its been holding for over a year now. very thin smear on both sides of the case and snout, is more than enough.
im sure it would be easier to work on off the car.