Ok, i know im prob going to be called a dumbass but in my rear drive shaft the 2 caps in the yoke on my M20 keep breaking the needles which therefore cause the joint to turn from metal to a black powder. So twisted yoke maybe? But it's brand new.........its go a Tom Woods rear shatf but the 2 in the slip yoke are perfectly fine but just the 2 in the yoke bust needles. If i run the dogshit out of it the joint will fail in about 3-4 days but if im easy on it they last 2+ weeks.....at least thats how long this ones lasted. I've gotten prety good on changing joints out quick but im tired of buying them, so what the hell? Auto Zone u-joints to blame? The spicer that was originally sent with the driveshaft had busted needles too.