I have a tandem axle under a P III, 1998 vintage. I have measured the unloaded ball height and it is 19″.When I hit bumps the trailer is rising off the ball and slamming around. The brakes are smooth; no clunking from them.I can easily raise the tongue off the ball without the jack. Should I look for a 1″ or 2″ increase in height for the receiver to eliminate this problem?Thanks.