If it is open the the inside tire seems to spin because it has less weight on it and it breaks lose. Most on road vehicles have open diffs i'd say. But i would have L/S if i could

__________________
2004 XLT ext cab 4.0
Add a leafs in rear and torsion keys in front
265/75/16 cooper discoverer AT3's
flowmaster super 44, 1 inlet 2 outlet.. cats gutted
pioneer head unit, hifonics amp, 2 kicker cvr 12"