yo,
This by our Friend, SEABRONC;
It is relatively a simple job. Just be careful not to lose any of the pieces. You will have to raise the window to the up position with the tail gate down to get at it and work from the side (driver side latch must be manually closed). Be carefull not to put any weight on the window or just to be on the safe side put something under it to support it. Then you remove a nut that holds the actuator arm on to the cylinder, a C clip, a couple of spring washers, a spring clip and the clip that holds the cylinder to the gate.
Mark the top of the lock before you remove it from the old tail gate. If you put it in upside down you will not be able to pull the key out. If that happens, take it apart turn it 180 degrees and put it back.
That is all I can think of off the top of my head.
Good luck,"