jeep, being the infinitly wise company that they are, decided that they wanted a slave cylender and throw out bearing in one. so when one fails you get to replace the whole thing. i've never actually had a throw out bearing fail on a jeep with an all-in-one unit, only the slave fails. it such a stupid waste of money and time i just wish they would have stuck with what works. at least they still understand that solid axles are the way to go on the trails.