I have a set of Dynatracs. I found them easy to install and the instructions were very good. I had experience with the lockouts on my '91 cummins and an older GMC so they were built like those, only heavier. Best I can tell they give me app. 1 1/2 mpg better mileage. They are pricey though. Make sure you use the socket on the steering knuckle? and power steering idea to remove the unit bearings too.