What did DSS say about them wearing out in 4,000 miles?There should be little to no play in the CV, a bit in the diff yes but little to nothing in the Axle. If you take the tire off and rock the brake disc back and forth watch the inner hub it should move exactly along with the disc. My DSS axels did not last very long, I just installed new ones 2 weeks ago, took all the NVH out of the rear, they where the source of the noise and vibration and only 4,000 miles old, externally they looked like new yet. They are rebuildable though. See in this video the inner hub does not move while rocking the disc back and forth? That hub should follow the disc with little to no play, hope this helps.