I have a 2005 f150 FX4/supercab with approx 110k miles. Trying to detect an annoying vibration on acceleration. It is somewhat detected at almost any speed but most noticeable between 50-55mph. Can see back end of bed shaking in side mirror and seems like it coming from drivers side. Doesn't seem like it involves anything in front end/ steering or braking.
I realize there are a ton of ideas out there and difficult to diagnose, however, this is what i've done so far:

New U joints/ and balanced drive shaft, new rear rotors and also cleaned and serviced the parking brake shoes and lever assembly, removed front leveling kit, changed out rear differential fluid and added friction modifier, also had tires balanced several times and road force tested.
I have taken into several dealers and the same old story of wasting time and money with no resolve. Other than suggesting that it is possibly a driveline issue? They also used a vibration analyzer that didn't help either.
I am almost to the point of throwing in the towell. But not sure if anyone can help or provide additional ideas ?
I've heard about : checking pinion angles, hub bearing assembly, or something in transfer case, but not sure if I can do anything else on my own.

thanks in advance

 

Talked to my friend the other day that had the exact same problem. Although his tires were balancing correctly on the machine, they were not balancing at high speeds. He had the tire store remove all the balancing weights from his rims and install balancing beads into his tire and it instantly took care of the problem.

Give it a shot and if it doesn't work, you are not out of a lot of money.

Also, you didn't mention that you swapped out shocks. At 110k miles, I'd throw a new set in. They are pretty inexpensive as well and could be the issue.

Good luck

 

Is anyone familiar with problems associated with 'Carrier race and bearings' in rear differential ?
and how easy is this to detect ?

 

Does anyone know if it is standard to run 'LT' tires? and if not having them could be reason for bed vibration( given the fact that they are balanced correctly)
My problem started when I put these tires on Nokian Rotiva AT 116T 275/65/18

 

Post removed because you crossposted to a new thread and there was already a reply. Don't do that, it's bad forum etiquette.