My husband went to get the truck detailed and the fellow says to hubby "Are you aware that the brackets attaching your 5th wheel hitch to your truck box are not secured to the frame, they are just attached to the box?" My husband was absolutely stunned, he got under the truck and the guy was right. We had the hitch professionally installed in Calgary 9 yrs ago! Hubby went straight to the RV shop down the street and the worker there said it is a miracle that we didn't lose our trailer. He also told us that we really should not have the box liner in the truck bed either, he said the spray on type liner is fine but not the black molded type that we have.
We are lucky in that we leave our trailer at a seasonal lot so aside from towing from the dealer lot to the campground we have not being towing our trailer around, but, we have bought/sold/switched trailers several times over the years and never had a problem with the hitch set up the way it is. Has anyone else ever seen this situation, the hitch brackets are only secured thru the box not the frame