went to change my trans oil today and the drain plug on the bottom of engine, the head is stripped on it and i was wondering how i might could get that off...kinda a dumb question i guess but i tried a few different things and nothing even budged it really...also it may be just me but it seems like the engine is making a knocking sound on the top portion...topend was just rebuilt tho...any info or help or opinions would be greatly appreciated