Since thenetguy has noticed that the vibration issue seems to be related to the bed, let's pool all the information we have to see if there are any correlations. Relevant information:
Body (Reg, SCab, SCrew)
Bed (5.5', 6.5', 8')
Speed

Helpful:
Towing Y/N/Weight
Drive (4x4, 4x2)
Axle (3.55,3.73,4.10)
Motor (4.6,5.4)
Tire Size (...)
Wheel Size (17",18", Custom)
Manufacture Date - Location (MO/YR)

We may be able to collect enough information to pass on to Ford and maybe expedite a TSB. So, please, if you have this issue, report as much information as you can.

I can pass this information to my brother who is a software/manufacturing engineer for Ford at the Rouge plant in Detroit, who then may be able to pass it on the the best people to look at it.

 

Sorry I forgot to let you guys know some important details. I have a 2004 FX4 with electronic 4x4 shift, SuperCab with 3.73 limited slip, manufactured in Virginia in late September 2003.

 

forgot a few more details - 6.5' bed, 5.4L engine, 18"wheels, BFGoodrich tires

 

screw
5.5
59-71mph
yes,1600lbs
4x4
3.73
5.4

18"
12-03 Kansas

 

Vibration or shudder? I've got the shudder or after-shock where the truck/bed shakes and lingers after small bumps.

SCREW
5.5 bed
40-80 MPH
Yes, up to 2500 lbs
4X4
3.73
5.4L
16" Generals
12-03 Kansas

 

New 2004 F150 Super Crew...4X4...LS3.55 Dif...5.5' box...5.4 l engine...AT

Intermittent vibrations (steering wheel shimmy) at 60-75mph. Feels like wheel hop and seems to increase in resonance over a short time and distance.

Opening the rear windows at these speeds also sets up a harmonic vibrating air mass that also gets worse over time that damn near hurts your ears. I think there is an aerodynamic airflow tie in with the steering wheel shimmy.

Wheel balance twice has not helped.

Ford better figure this out or they'll be buying a lot of trucks back.

My 2000 F350...4X4 crew cab long box was a much better truck as far as ride and handling goes. No vibrations there.

 

High frequency vibration felt in steering wheel. Starts around 40 mph, most noticeable around 50 mph, and disappears about 60 mph. Not pronounced enough to see the steering wheel move, but can feel it.

Towing: no
Drive: 4x4
Axle: 3.73 LS
Motor: 5.4L
Tire size: P275-65-R18
Manufacture Date: Feb '04 Norfolk VA
Bed: 6.5'
Tires: BF Goodrich
Odometer: 810 miles

 

Noticeable 70mph steering and some Bed vibration
-2004 FX4 Screw
-5.4L
-3.73
-7200 GVWR
-6.5' Box
-P275-65-R18 BFGs'
-Manuf: Norfolt Virginia Plant 01/04
I would love to get to find the issue!

 

Box shudders most at 55-65. Continues to shudder over smaller bumps like the rear of the truck is bouncing with no shocks. Got so bad once the gas cap popped open and took to the dealer. The spring mechanism fell out of the gas cap closure unit...probably due to the long trip I took with the prolonged vibration issue.

I like eauclaire's idea and I'm more than willing to assist with a resolution. I found the way to replicate easily, but don't think it's drive train related. Wonder if you guys are trying the "tailgate test" I mentioned?

SCREW
5.5 bed
55-65 MPH
Yes, 5500 lbs
4X4
3.73 LS
5.4L
P275-65-R18 BFGs' Rugged Trail (not sure how 4 ply is rugged)
10-03 Kansas

 

p.s. Box doesn't shudder when towing or with 500 lbs. or more.

Smooth as silk, but not very good on the gas milage! :-)
Hey! Maybe they can pass out bags and tell us to pound sand?
Sorry, Got to keep the humor going so we don't go insane.

 

About the vibration, it seems to happen when your moving forward at higher velocities. Right.
Does anybody have a Tonneau Cover (Soft or Hard)?
I wonder if it could be wind drag.
Does it also happen with the tailgate off or open?

I'm wondering if the people that it doesn't happen to, they all have covers, a lot of weigth in the back, maybe even a bed liner, if that is the case, that means that probably every truck as the problem.

I guess probably, that it wasn't a good idea for Ford to screw the box, instead of having it spot welded.

Can anybody check if the screws holding the box are screwed in tight?

I wish I could test it on mine, but I'm still impatiently waiting, dealer told me around the 15th of April.

Good luck

Ron

 

I just got a bed cover this past weekend. It is a hardcover made by Undercover. It is fairly light weight, weighs approx, 60 pounds. Also have a bed liner. I don't think it is just a wind drag problem because I am still experiencing the feedback in the wheel the same as before. I'll let you know tomorrow after I have the dealer give me an alignment if the problem is taken care of and what they say about the feedback.

 

Same here. I have a Lo-Rider hard tonneau and it had the bump shudder before the tonneau, and after. It's the chasis. Ford knows it, and that's why they've come out with a lame "fix".

 

Took my truck in this morning. They said the alignment was off and I have picked it up. It drives better naturally but still some vibe at 55-60mph. Mostly just excessive steering wheel feedback. I told them about the problem when I dropped my truck off and they called to say it was ready and told me the tires were low and that was the reason for the feedback in the wheel? Rather than argue with them I just said okay and will drive some more before taking it back again to see if the alignment was the problem an if the feedback gets any worse and make sure it holds the alignment.

 

2004 F150 Lariat SCREW 4x4 5.5' bed 3.73 gears

Bad after shock when bumps are incountered steering wheel shimmy above 50mph that comes & goes for no reason. Bumps carry through to the steering wheel. I have a soft locking tonneau cover but I still have the problem. My gas mileage went up fronm 11.1 to 12.2 so that's 1 good thing