2002 Mitsubishi Montero Montero Sport - entire vehicle shak

Shakes or Wobbles problem
2002 Mitsubishi Montero Four Wheel Drive Automatic 65000 miles

2002 Mitsubishi Montero Sport 4x4 whole vehicle vibration at and above 45 mph causing the vehicle to growl. It dosen't start to vibrate until 45mph and it does not stop when you reach a certain speed. It is continuous at 45 and above- you can feel it in the entire vehicle. I am a very experienced mechanic but I am stumped. I have replaced the axle bearings, wheel bearings, U joints, tires, and rebuilt the transfer case.