I think i have the dreaded vibration issue and was wanting some advice. My Truck is a 2010 FX4 crew cab with the short bed and 60,000 miles. When i first got the truck Ford told me the vibration I was feeling was from flat spots on the tires. When I took my truck in for tire balance tire store told me that the tires that were on my truck were not the best and that was causing the vibration. I just kept driving the truck thinking it was the tires. Fast forward I replaced the tires last year and still can not get the vibration out. It is really bad around 40mph to 50mph. I do not feel it in the steering wheel mostly in my seat. I have rotated my tires and the vibration stays consistent in my seat. I thought it was maybe something my tire store was doing so I went to another tire store and had them road balance and rotate my tires the vibration stays consistent. I started searching the internet and it seems Im not the only one experiencing this. My dilemma is do I start replacing parts to try and resolve the issue? Some have said it was the driveshaft and some have said it was multiple other parts. Some have replaced everything under the sun and problem still persists. As much as trucks cost these days I do not want to have to buy another truck. I am thinking of having the driveshaft replaced but don't want to spend the large sum of money and still have an issue. What do you think I should do?

 

On every vehicle I've worked on for a vibration I've always subscribed to the theory; If you feel in the steering or more towards the rear of the vehicle start the diagnosis with the wheels, tires, and suspension. If you fell it in your *** in the seat start with the drive train.

With what you describe I'd pull the driveshaft, have the u-joints replaced and get it balanced.