Seems like what we want is a simple safety measure to add in the field.
The challenge is how to stop the big pushrod tube from rotating clockwise onto the long rod end shank, which can allow the rod end shank on the other end to become unthreaded.
Try this.
Add another nut to the shank. Spin it all the way onto the shank until it bottoms on the last thread, near the head. Install the pushrod, adjust to length, then measure the length of the threaded shank showing between the new nut and the original jamb nut. Obtain a short length of thinwall steel or aluminum tubing with an inner diameter as necessary for a slip fit on the rod end shank. Cut it to the correct length to fit between the nuts and install it there. Again check pushrod adjustment......control travel as necessary while maintaining enough rod end threads in each end so that even with the jamb nuts loose the pushrod cannot rotate and unthread at either end. Tighten and mark the jam nuts.
If you're the nervous type you can sleeve both rod ends.
