The needle bearing are located inside the bearing hub, not the locking hub assembly. To replace the needle bearings you would have to pull the 4 nuts on the rear of the hub assembly remove the whole hub and R&R the needle bearings in the center of the hub, this is the faulty bearing, check your axle stub too while you have it apart. Don't replace the whole hub this will cost $350.00 to $400.00 a side.