55.2-59 Urethane tailgate trunions

[NWA58]

Anyone have experience with urethane tailgate trunions? I finally have my truck painted and assembled, so still trying to fine tune and get to know what I have. Trailered it about 60 miles after assembly and when I got it home, the tailgate trunion bolts (essentially, the hinge) had backed out and were about to fall out. Tightened them up and did a couple of runs down the street before later taking a first drive on the “big road”. 10 miles round trip. Got home, pulled into the garage, found my tailgate hanging by a strap, and one of the Trunion bolts gone! The other was loose but still there.

I’ve got the first Mar-K tailgate they produced with the licensed GMC logo and push button latch. Now that Mar-K has closed their doors, my tailgate is irreplaceable. With the hidden latch, there is no need for chains and hooks, so those were not there to hold it up. I was able to reinstall the gate, and adjust the latches to be sure that both sides are secure. And to keep those pesky bolts from backing out again, they got a healthy dose of thread locker.

So with everything tight and bonded, I have a squeak from the urethane rubbing paint inside the roll when lowering the gate. I’m not sure if I over torqued the trunions and they swelled a bit, or they are just properly tightened and need some lubricant. I’m sure my Mar-K urethane trunions were produced elsewhere, as they are still sold by others. What are you guys using as lube in there?