Tow a 2800lb 17ft TT, with WD hitch, 6.4 2500, tows like its on rails, passing,crosswinds all great. But when towing my 20ft runabout, 4.3 liter I/O not quite as steady. Recently, I was getting sway on the back, sometimes it would come and go, it was a bit nerve racking. Wasn't sure if the boat was centered, or loaded on the trailer, so adjusted bow roller, changed to a different drop hitch still terrible over 60mph. Had the wife stand on the rear platform in the launch parking lot, we shook the boat as hard as we could, Holy crap!, the center frame rail, where the two outside rails meet, were moving, ALOT. The rails are 2x6 steel, the angle brackets that bolts inside the 2x6's were 4-5 turns loose, ny-lock nuts had backed off. With the end caps on, you could not see them. PIA to get them tight with the tools I carry on the boat, but was able to mostly tighten them for the trip home. Fixed even tighter, when home. All bolts on the trailer, were checked a few were also loose. Tows great now. Gentlemen please check those nuts!