A friend of mine told me that if you put a small amount of ATF in your oil about 200 miles before the next scheduled change, all the extra gunk will loosen up and come out with the oil. If this is true then here are my questions: what does ATF stand for(that's a stupid one, huh?)? Where can I get it? Will it hurt my enginge? How much should I put in? Thanks for the info in advance. 

Thanks though.