I just did one big stupid late this afternoon. I've been working on the new to us unit and have finally finished most things. The unit was sitting in the middle of the driveway with all the slides out, and a big snow storm is on its way. Decided to close it up for the rest of the winter and move it to one side. Hooked up to my tow vehicle-checked the hitch & the jaws sure looked closed & locked. Slowly pulled ahead and huge crash- the hitch jaws were NOT locked and I dropped the trailer down onto the F350 box. I managed to get the trailer up enough to get the trailer off the truck, and then worked with a couple of jacks to get the trailer back up high enough to re-hook it. I have a new appreciation about just how heavy these trailers are- both from the damage to my truck, and the fact I tried my 2 1/4 to floor jack to raise the trailer and it didn't move it. I went and bought a 12 ton bottle jack to jack one side and floor jack on other. Finally got it lifted back up.Truck box looks like someone did a karate chop across the box, driver's side is creased down about 5 inches- it buckled the floor in the middle of the box. So far I cannot see any damage to the trailer, but I am concerned about hidden damage. I'll check the bedroom slide tomorrow and see if it works. I'm in a dilemma whether I should report this to insurance. Hopefully a nights sleep will clear my head. Any thoughts about what I should look for in and on the trailer?