hey guys,i have this brandnew spare diff case came from my hyper 7 when i bought it from a friend,but this one is different the diff case which i use on my hyper st has a metal tip on it which we usually insert the drive cup,but this diff case that i have all composite there is no metal diff ring on it,i try to build it to use as spare my front diff,but it wouldnt spin freely,can a file the plastic ring so it can spin the diff withou any binding?