im brand new to the old truck thing. been doing choppers for years and decided to cross over. i have a huge problem! just picked up a 64 f100. c6 trans, 390 merc and a 9inch rear end. there is a huge clanking noise coming from the rear end when ever i am at low rpm and turning right or left. going straight she flies and there is no issue. i checked the u joints, seem good. drive shaft looks good. and i have oil in the diff. not sure what it is? also hearing a winding noise in the cab almost like something is turning on electrically when i am at low rpms and stepping on the gas. this is a seperate issue fromt he rear end. any help would be greatly appreciated!

 

maybe the rear end has a locker in it?

if you jack up both rear wheels and spin one...does the opposite side rotate in the same direction, or backwards?