I have a '04 Dodge Dually. I suggest you remove it at home or have the dealer (Dodge or TC) show you how, then take the truck home to remove and store the tailgate. It is heavy.
First look between the bumper and tailgate for the Tailgate light wires. They connect behind the bumper just below the top. Disconnect and route over the top of the bumper.
Lower the tailgate about 45 degrees. There is a cable on each side of the tailgate, held in place with a flat spring. Raise the open end of the flat spring with your finger and lift the cable eye off the pin on the tailgate.
The bed of the truck has a large cup (abt 1-inch dia.) on each side at the bottom of the tailgate. The tailgate has tailgate has a pin on each side that goes into the cups. This is the hinge. One of the pins has two flat spots an with matching openings in its mating cup. With the tailgate about 45 degrees, lift one (right side I think) end up out of the cup (while pushing tailgate to opposite side) and sit this end of the tailgate on the bumper. Then, holding the weight up on the opposite side, slide the tailgate off of the remaining cup and sit it on the bumper.
This tailgate is not only heavy, but awkward to carry. I am 6 foot tall, 280 lbs with long arms. I can get mine off the truck, but need a hand truck to move it around. I would not want to get it out of my TC or the back seat of my Quad Cab, doable but prefer not.
Wayne