\ 4Lo-Trac Hack (A-Trac) for Non-Locking FJs: Does it work, Yes! How does it compare to A-Trac, only time will tell... Intro: All of you know by now that if you didn't get an FJ with a rear Diff Lock, you automatically didn't get A-Trac. Now surprisingly, the locker has nothing to do with A-Trac, its just that Toyota apparently thought that if you don't need a locker you have no use for A-Trac ether. Looking at the difference between a Locking FJ and Non-Locking FJ you will find only one difference that has anything to do with A-Trac, which is the Brake Computers Part Number (The one mounted to the Brake Booster). to complete this description visit this site http://www.fjcruiserforums.com/forums/4x4-off-road-tech/75347-4lo-trac-hack-trac-non-locking-fjs.html