I have a 14 bolt ff axle that I want to put a locker in. I was leaning towards a Detroit but I dont understand anything about them. First, do they go inside the carrier or replace the carrier? If they replace the carrier, do I need standard gears or thick gears (5.13)? Second, how do they work? I mean, how do they know the difference between making a turn and a tire slipping in mud? Third, how long do they typically last?


Sorry for the dumb questions but these are really expensive and I want to make sure I completely understand them before i shell out big $$$ just to end up with headaches and wrong parts.

This link will explain how lockers/open diffs/limited slips work.
http://reiderracing.com/rtech_diffs.htm
Most full case lockers will replace the carrier they actually are the carrier, there are lockers that replace the side (spider)gears and are often referred to as lunchbox lockers.

With the 14 bolt the Detroit goes inside the carrier. Theres more to it than that but thats a pretty basic breakdown of your question. Before you do anything spend some time researching so that you know what your getting yourself into money, labor, how it affects your vehicles handling etc.