I have power locks in the front and rear of my CJ and they have served me well so far, but a jeep is never done. I rebuilt the 44 rear with an aggressive rebuild kit less than a year ago and it has worked well, but I want a full locker in the rear so I'm putting in an ARB. Because of the risk of breakage I want to keep my front dana 30 Power-lok rather than locking the front, but want to make it lock up stronger. How do I know if it is worn out (both tires still spin when jacked up and one is turned) and how do I rebuild it or shim it to make it more aggressive? I have heard of people putting shims in them, but am not seeing the specifics on how thick the shims are. I have also heard of people doubling up on the cones, but I'm not sure my frond dana 30's powerlock has the cones or not since I haven't taken it apart. I wonder if I can even just shim the clutches I have now if they aren't worn out. Please help me build a more aggressive powr-lok. Thanks for your help.