I had a gooseneck hitch mounted on this truck and it pulls fine but I found that although I'll stop fine without a load on the trailer when I put a tractor on the trailer and come to a stop after my speed gets down to about 20 miles an hour the whole truck shutters. It doesn't do it when there's not a load on. Just wondering if anyone else would ever come across the problem like this. I did follow all the instructions leveling the controller making sure that it would just barely not lock up the wheels when I stopped, and it all stopped fine in that position when it was empty. But put a tractor on it with the same setting and it shutters unless you back off the power on the controller then it doesn't want to stop very well. Appreciate any ideas as to what might be the problem.