I have a fairly stock TJ. Stock axles and steering linkage on 31x10.50 ATs. I was on a trail this weekend when I lost steering. I looked under it and found the cotter pin and castle nut that hold the drag link to the pittman arm were gone and the drag link was hanging. Luckily, it didn't get bent. The castle nut is the same size and thread as a lug nut. I stopped every 30 minutes - 1 hour and checked to make sure it wasn't working its way off until I was off the trail, never came loose.
EDIT - I trailered the Jeep there and back.
DISCLAIMER: Do not drive on the street without the cotter pin in place.