My 2009 F150 4.6 4x2 has an intermittent vibration that occurs during highway speed. I had an alignment done, I have brand new tires, and even picked up a new OEM wheel to replace a slightly warp on. Yesterday I replaced the original U joints, thinking they might be worn and throwing off the balance of the drive shaft. I still can not get rid of the shimmy. It's not coming through the steering. It feels like its coming from the rear end. And as I said it's not constant. It comes and goes sometimes when I let off the gas or add power and sometimes after braking. While replacing the U joints I didn't see anything visibly wrong with the drive shaft, so I don't think it's that, but I could be wrong. I do have a slightly warped rear disc rotor that causes constant shimmy when braking, but this feels more like a bad tire or something.

Any suggestions? I don't know what else to look for at this point.


Thanks in advance for any help!

 

I do not know if this can be of any help but my 2001 F150 has had a vibration problem when I haul a load. The Ford dealership said my front ball joints had slack in them. Your question said yours is a 2009 truck so I may not have been of any help.

 

It's possible that warped rotor could be causing it.