Let the tailgate down half way, unclip the side support cables from each side (tang pulls away allowing clip to slide up and off pin) and pull up/out on the right hand side of the tailgate. Raise or lower tailgate to find the opening slot in the hinge. Once the RH side is free, shift tailgate to the right and it will slide off the left hand hinge. Don't loose the plastic bushings from the hinge! THE TAILGATE IS HEAVY, SO USE 2 PERSONS OR BE PREPARED! Replacement is reverse.
NOTE: IF YOU HAVE A DUALLY, DON'T FORGET TO DISCONNECT THE LIGHTS FIRST! The plug is under the bed on some, and between the tailgate and bed on others.
Jeff