Made a 20 mile trip into town to pick up a couple things and wash the blue beast. Pulled into the car wash stall, put my foot on the brake, grabbed the shift lever to put it in Park and it started flopping around like a limp noodle... Almost shut off the truck, but then realized it wouldn't start again if I couldn't get it into Park or Neutral... since it was still in gear I just headed home to troubleshoot it. The shift flopped around so loosely that I was convinced something had broken in the steering column, but it turned out to be much simpler... the cotter pin at the final connection under the truck had broken off and the linkage just fell apart. A small washer and a cotter pin later everything was back to normal. Guess cotter pins are only good for about 245k miles... Just wanted to share my "oh crap" moment in the hopes that it helps someone else in the future.

 

Had a very similar experience about 3 years ago when the plastic connector part the keeps the shafts in the holes of the levers on the transmission itself finally wore enough to pop out!

Dealer didn't have any - had to order it so I had to put the rod back in every time I went to start the truck and shut the key and put the parking brake on when I parked.

 

That was very smart of you not to shut the engine off. Way to go!