This is where a "been there, done that" fits...
Last year new 2011 F250 long bed and had to pull the 5th wheel forward about 2 feet to reach the power plug on the rear of the 5er. Backed back under it, heard it click and got out and raised the front jack enough to clear my block and pulled forward. The truck moved and the 5er didn't except to crash down on my bed rails. What a heart stopper that is.. Glad I still had jacks down some because it only bent both sides down about 4" and tail gate was down so that was spared..
Since then I have my head in the bed of the truck making sure those Hensley Trailer Saver Jaws are wrapped all around that pin and I use a lock so no one can trip the jaws while I'm away from the truck. If we stop for lunch or leave the truck for any reason while traveling with the 5er, I stick my head back under there to make SURE that sucker is hugging the pin.
They say you'll only do it once, I'm making sure it don't happen again.
Don't be like me, I always said that would never happen to me...Will it did and what a way to learn.
2011 Cedar Creek 36B2 ordered with outside kitchen removed and a nice big wardrobe in it's place.
Pulled with a 2011 F-250 Super Duty 6.7 Diesel Crew Cab and 8' box with a Hensley BD-3 Trailer Saver. F R O G members.