A customer of mine just bought a 2004 ford f150 supercab 4x4 with 5.4 V8 with about 47000miles. He is saying there is a vibration between 40-60 miles an hour. We have put new tires on and a new drive shaft. Still there is a vibation. Any input to fix this would be great appreciated!

 

I assume the tires are balanced...?

 

The tires are new and have been balanced. We even balanced the old tires before the new ones were put on and still there is a vibration. New tires and new driveline has been put on. The vibration happens when the truck goes over some bumps on the road and has a hard time dampening the vibration or keeping it from vibrating longer than it should. Any ideas would be very useful