2003 Ford Escape 2003 Ford Escape Shakes at greater than 40

2003 Ford Escape (4x4, V6) The engine runs smooth and is a perfect car as long as your speed is under 40 mph. Once over 40 mph it begins to shake. The feeling does not come through the steering wheel so much as it does the whole car. At 50 mph & up the shaking increases. I have had it to 2 mechanics & have had the following completed.
1 Placed new tires on the front of the car. All the tires were aligned. The second mechanic alligned the tires (shaking continued)
2 The ABS light came on and half of the axle was changed out to fix that problem. But the shaking continued.
3 The first mechanic sent it to a tranmission specialist and they said the tranmission was in great shape.
4 The first mechanic changed out drive shaft (used) under warranty I purcahased and the problem did not stop.
5 The second mechanic felt it may be the carrier barring and the warranty company sent another used drive shaft to replace the first one put in.
6 Next on the list is motor mount? Any suggestions?