New ring and pinion, new driveshaft, new limited slip, etc. It is great now. My hats off to the little dealer in Loveland! They were great!

 

Hehe...yeah, me too!

 

My 06 xlt 4x4 had a vibe at 50-55 pretty bad that you could feel in the seats and dash. After 2 trips of them telling me that it was the tires and that they fixed it, I called corprate. They scheduled a test drive and I took the dealer forman with me. It only took seconds of listening for him to say, "your lash is out on your ring and pinion. Your rear axle probably needs to be shimmed too." 2 days later and the Vibe was gone. Then on to the steering wheel shimmy that was caused by a warped rotor that was fixed and the crappy General tires that Ford put on the chrome clad crappity crap 17's. I got ahold of some 20 inch oem alloys and had some Cooper Zeon's put on at discount tire and that solved that problem.

 

It has been my experience that 90% of the vibration issues have to do with the wheels and tires.
Kid you not.
This truck has the MOST sensitive steering everr.
Discount tires helped me. They had been with a man who sold his truck over this issue and they could not help him.
I was determined.
First they found 1 bad tire. We put it on the front , the steering wheel when bonkers. We moved it to the back and the gas pedal when bonkers.
I ordered 4 new tires (later met someone whose wheel was bad).
I WATCHED them force balance the tires.
I said I would not buy a tire which did not meet the machining standards which are spelled out on the Internet (by the way). The mechanic doing it said they cross those lines "all the time".
3 tires were good, one was 'good' via the mechanic, but not according to the Machine specs. I called the head honcho.
He ordered a 4th tire and it passed.
ALL VIBRATIONS WERE GONE AND HAVE BEEN FOR 60,000 MILES.