Fabrik8 is absolutly right about what it is doing to the axle nut. However, this is the solution for our years. I don't fully understand what causes it. I just know the way the axle splines and the splines inside the hub mate causes a "click", and the only solution is to torque the nut tighter and grease the splines. I have had mine at 250ft/lb for 2 years and 45K hard miles w/o any problems. But I still get the click every once in a while. You learn to just not care anymore since it is not hurting anything.