The exact same thing was the case with me. Old factory lockouts were bad, or so I thought. After spending cash on new hubs and them not working either I figured it out. Short stub axle was broke clean. That is how i purchased it, not knowing. Check your axles first. Pull off the differential plate and your tire (to make it spin easier, while in the air) and spin the axle by hand to see if it spins the gears....
BAIL! "Welder's have hotter rods"
Arc-Up Welding Inc.