Write down your particular vibration problem (briefly) like
"truck vibrates Most noticeable when driving up inclines where the load increases, and between 60-65 mph. The steering wheel really doesn’t shake that much. The shake kind of feels like a whopping sound, and is louder with the windows open.
It is worse when temperature is hot. .
It is worse and howls with window open"

and Include specific truck data ie.:
04 150 sc 4x4, 145" wheel base, 9.75 rear end, 3.55 ls 165x17 wheels drive shaft number(s) 4L4z 4K124 TA,

and list the parts they replaced which did not help:
replaced drive shaft 3 times, added dampner,
etc.
The key to this poll will be in what you are 'feeling' or hearing in the truck and what type of truck it is. It will be up to us to find the common issue and what might be the answer.

 

Vibration is continuous throughout driving speed, but is most severe at 65-70 mph. Steering wheel vibrates, keys rattle in dash tray, doesn't change if I accelerate, definite 'howl' with windows open. can't hear a change if I leave tail gate down.

04 150 sc 6.5' bed, 5.4 motor, 255x17 tires, 3.55 ratio, 9.75 rear, ls axle: 4L34-4K145-TE, truck made in Norfork, 7/03

 

My vibration - truckbed cha-cha more approrpriately - happens between about 55-60mph. Can really see it shimmying (sp?) in the side view mirror. I can feel it in the steering wheel and in the pedals.

My truck - '04 4x4 SuperCrew. 5.4L engine, 3.55 gear ratio. 255/17 General Tires. Assembled in Kansas City, May 2004.

 

First let me say that I am not in your boat as far as vibration is concerned. Second let me say that even the sales people have a hard time getting it fixed. I bought an XLT made in June off the recommendation off of my dad's friend who is a Ford Salesman for Ricart in Ohio. He bought it in January or February and after a new tranny, the dampener, and driveshaft it still isn't fixed. I know it sucks but Ford is sticking it to their own people as well. The sad thing is when I asked the guy about Clutch Packs, he had no Idea that was even an option and he was wating for a ford engineer to come see him, this was last week.

Jansen

 

Let me be clear, I did not buy my dad's friends XLT. I bought one nearly identical to his. Only difference is mine is on the tree his is on the center console.

Jansen

 

tried something new. Put the tailgate down 1/2 way-not flat down and the vibration lessened!!!

 

i had a tiny one that my dad noticed in the steering wheel but found out when they put the mickey's on they didnt balance them right lol oh well no vibes anymore only tiny ones when i tow. but i think that normal.

 

If you look from the driver side rear wheel well with your eye level even with the top of the frame you can't see the rear passanger side tire, Now do the same from the passanger side rear wheel well, you will see the top two to three inches of the driver side tire. The frame is uneven and unbalanced with the axle. Every F150 on the dealer's lot is the same way, this is the crux of the vibration issue. Wake Up FORD

 

KN127, you described my condition exactly.

Most noticeable when driving up inclines where the load increases, and between 60-65 mph. The steering wheel really doesn’t shake that much. The shake kind of feels like a whopping sound, and is louder with the windows open.

Temp sometimes plays a role.

98 150 sc 4x4, SWB, 9.75 rear end, 3.55 ls 165x17 alloy wheels
conventional steel drive shaft

Replaced everything but the rear end and wheels. Been through three sets of tires (good year, dunlop, uniroyal), so it ain't the tires or balance weights.

Think there is something funny with those lug-nuts.