I've got a Summit running dual Kershaw DeWalts, HR steel spur gear and heavy duty slipper. I was recently running around the back yard when I lost all grip in the slipper. The locknut on the slipper had screwed itself all the way out to the end. So, I tighten it back up, drive 20 feet and it wound right back out again. Ok, replaced with a new lock nut....still doing it. Added a washer between the spring and the nut as well as a new bearing at the other end of the spring. No luck.

Any ideas?

Also, I have almost a full rotation of the spur gear worth of play, is that normal? Is it time to rebuild my gears?