Several folks have noted "lockers" will help traction. I'm aware of the Powertrax locker and am wondering if these will fit a 2WD 05/06 Xterra with an automatic transmission and factory limited slip. Does anyone know what differential is in that model of Xterra and the # of splines? Has anyone installed a Powertrax in a 2WD 05/06 Xterra? Thanks.