Just like my 10-bolt did before, my 9-bolt started to whine after some enthusiastic driving. The whine is pretty faint still and hard to hear but its definatly there and it wasnt there when i put it in. My 10 bolt whined so bad after awhile that i couldnt even hear the radio, just the loud whine of the rear end. What is causing my rears to do this? Is the backlash opening up? I remember from somewhere that it can open up when the crush sleave compresses from hard use.