If there's any complaint I have about the Andersen 5th Wheel Ultimate Connection Hitch, it's that the frame has been wearing down the Line-X bedliner in my truck.
Other than that, I'm very happy with the hitch.
So I read on some other forum that someone solved the problem by putting in a hard rubber (like tire rubber) mat that he got from Tractor Supply Company. It's a 4' x 3' Utility Rubber Mat, 1/2" thick. It's very hard and dense and heavy, weighs around 40 lbs. It's listed under the department for Equine Horse Stall mat. It cost $26.99 plus tax.
I used a 2-3/4" hole saw on my drill to cut out the hole for the ball. I drilled halfway through, flipped the mat over and drilled the other halfway through for a clean cut. I also cut 2-1/4" x 1" slots for the safety chain U-bolts.
If you notice in the pictures, I did not center the hitch on the pad forward to back for a reason. I have some storage bins that I carry in the truck bed between the hitch and the tailgate and if I had the pad centered, then the bins wouldn't fit and the tailgate wouldn't close.
Very happy with the results!
Recommendation: Do not go with a thicker pad. I think TSC has a 3/4" pad which would probably be too thick to get the hitch receiver pin to get under the gooseneck ball. 1/2" was just enough. You could cut around the receiver box on the hitch, but I wanted a clean round hole instead of a square oversized hole.
Tip: Use a carpet knife with a new blade, commonly called a utility knife or box cutter to cut or trim. Also use a chalk line to snap your lines. I used a 2-3/4" hole saw to cut out the hole for my gooseneck ball and it's perfect.
I tightened the hitch down to 60-lbs, and after I get the trailer on the hitch and moved down the road a bit, I'll check and tighten to 60-lbs again. I expect there will be some compression of the rubber mat, although not much.