Put one in my wife's XJ to replace the bad vacuum motor. Easy, took about 45min start to finish. Advice: Use one of the uni bits to drill the hole in the firewall, it will go much faster and smoother. Also, make sure you route the cable correctly or you can melt it on the exhaust or have it wear on the tie rod, etc. Have had it in for over a year now with no problems
To use it you just put the xfer case in 4HI and pull the cable out to engage the front axle. Not much to it.
Got mine for 75 bucks from a guy who bought it an didn't use it. :flipoff2: