The Powertrax No-Slip is an automatic locker for the Chrysler 8.25" 29 spline axle. It works in the rear of 2002-2007 Jeep Libertys, but is incompatible with Dana 35C rear axle found in some 2002 Jeep Libertys and might be incompatible with ESP system found in all 2006-2007 Jeep Libertys. While specially designed to eliminate the ratcheting sound that most automatic lockers make, it is still a little noiser than some may like. A "lunchbox" type device, it replaces the internal parts of the stock carrier. The 92-0382-2905 model is for open carriers and the 92-0382-2925 for Trac-Loc carriers. No ring and pinion gear set up is required and installation shouldn't take more than a few hours.