I installed my DZ about 6 months ago and I am having a lot of trouble understanding why some folks have such a lot of trouble with that nutsert?!?
Before inserting the nutsert tool into the tailgate, I adjusted the black bolt, the one with the 5mm hex in the top until the threads of that bolt were level with the end of the nutsert, the end which will be inside the tailgate. I then inserted the nutsert into the hole in the tailgate. I colored one face of the regular nut so I could count turns. I then put a 5 mm an Alan key into the head of the bolt preventing the bolt from turning and tightened up the nut on the threads until it just contacted the washer. I then continued to hold the bolt from turning with the Alan key and tightened the regular nut the required 9 turns. I pushed on the Alan key forcing the head on the nutsert to remain firmly in contact with the tailgate. This also prevents the nutsert from turning when you are tightening the regular nut. This expanded the nutsert inside the tailgate. You must not allow the bolt to turn, only the regular nut that is on the shaft if that bolt.
This worked for me. Am I missing something?