Rattle guns r ok 4 doing up just a bit tighter 2 undo, I,ve done a few diffs ,here,s what you do. Get a set of ramps reverse the beast up there so it,s ass is off the ground, now climb under there with the right size socket {at least half inch drive!!!} make sure it,s in gear with hand brake on,now slide a length of pipe over socket bar handle and yank it in the direction of undoing it,ll be tuff u just gotta hang in there!!!! Note THE LONGER THE piece of PIPE and the HIGHER the car off the ground the easier the job will be... So if you know somebody with a hoist that,s the go!!!! So what r u replacing it with??