I never liked that my '08 JK's tailgate had no provision to keep it open. Gas struts were not the answer for me, either.
When looking at a 2012, JK, I noticed it had a conventional door check on the tailgate.
So, I went to the parts department and looked it up. I had one the next day.
I wouldn't call this an easy installation, at least for the first one.
1. A photo of the tailgate check rod as received from the dealer.
2. The first thing I did was make a template of the mount, including pilot holes for the mount bolts.
3. Use the template to drill the pilot holes in the body, secure in place, and scribe the opening. I looked at a 2012 and placed the template in approximately the same location on my 2008.
4. Center punch, then drill the four corners.
5. Cut out the opening, and drill the pilot holes to size. I used ¼-20 screws/nuts to mount the plate.
6. This pic shows the reinforcement plate which I had to make for the tailgate. The OEM installation is reinforced on the inside, which cannot be accessed after the tailgate is built, (without cutting and welding).
7. Here is the check rod assembly in place. But don't close the tailgate yet...
7a. Make a cut-out in the inner panel to clear the check rod when the tailgate closes.
8. ...and here it is in service.
The check rod works very well. It only holds the tailgate open. It doesn’t serve as a travel limit. Tailgate open travel is still limited by the hinges.