Just wanted to let you guys know about the experience my wife and I had yesterday towing a maximum load of 9500 lbs. with my new truck (550 miles) and going a distance of 28 miles with the "big tow" package. I also had installed before we left an electronic power brake control for the trailer. We started out great going 40 mph, but then all hell broke loose. As soon as I got her up over 40 mph the trailer and equipment that I was hauling started to fish-tail like crazy. Needless to say, my wife "flipped out" and I was not a happy man. The only way I could stop it was to use the manual brake control to get the trailer to stop fish-tailing. As long as I didn't go over 40 mph, everything went OK. Lesson learned.