Seeing as how the drain plug will be messed up, and you need a new one, replace it with a magnetic plug. Caterpillar has some dandies. I put them on the fill too, so every time you check fluid level, you get a read on what is going on in that compartment. Little pieces of metal tend to raise heck with carrier bearings and ring/ pinion surfaces, and hd. pumps don't like them either.