I have a 2010 Fuzion FZ383 Toy hauler 40 f00t 3 axles. I had a Flatbed installed on my F450 Ford. Because it set to tall I went with a gooseneck adapter to pull with. Long story made short after 2 yea...
Place a piece of tape vertically on front cap about 8" long
Place a ruler on pin box vertically and mark the tape 'at rest' (not hitched up) Do the same after hitching up ---full weight on pin box
Should be 1/4" or less difference between the two marks. More then that.... Remove 5vr overhang panel (around pin box) and inspect pin box/overhang structure for distortion, cracks, broken welds etc while hitching and unhitching