I had a locker in the rear of my old F-250 but I didn't take it off road much,my last F-150 had a factory limited slip with 31X10.5 MTs,it got around great.
I bought the D44 from a NAXJA member/vendor out of Yakima,he was coming here to pick up some laser work so he dropped it off.
I gave $250 for it,its 3.55/open.I also got some disc brake conversion brackets from him.