I was coming up the four lane today when I saw a red/tan lariat like I have ordered so I sped up and got in behind it just to watch it and look at it since I dont have mine yet.
When we stoped at a red light and pulled back out I noticed at about 30 to 55 the bed was shaking so bad on this truck it looked like a 82 toyota that had half a rusted bed flopping in the wind.
I got beside of the truck and watched the bed and it was just flexing from mid wheel arch back to the tailgate and it was flexing so bad I thought the tailgate was going to work its way loose.

Has anyone found a cause for this?
How many people have had issues with this?

I really hope mine does not flex like that one was.

And so far today I saw 6 new 150s one black FX4, one silver FX4, and 4 red/tan lariats I am kinda down about this, since mine is red/tan I cant believe so many people have got red/tan in my small area.

 

I can see my bed shake in my outside mirror. I just went out in the garage and banged down on the corner of the rear bumper and I can see and feel the side of the bed vibrate for about 3 seconds after i bang down on the bumper. I don't know if other makes of trucks do this or not. I will try to do the same on a Chevy and see how it's bed responds. Maybe its this new 9 times stiffer frame. I think I will follow my wife while she drives the truck just to see how bad the shake is another drivers perspective. I have the FX4 Screw 18" wheels.

 

I didnt notice this on my 02 supercrew or my 98 supercab, I know the bed moves to some extent on flexing etc.
But man this truck was on a smooth road and the bed was moving bigtime.

 

the bed appears to move because of how the cab is mounted. the cab is mounted on bushings that move as you pass over bumps, thus making you think that the bed is moving. but, in actuality, the cab is doing its job by soaking up the bump and making the ride smoother.

.02

 

I don't understand it. The bed is bolted to a very stiff frame, stiffer than previous models. How is it going to shake unless the bolts are loose? The cab is soft mounted and intended to move. I drive mine through some big potholes and barely see a wiggle between the cab and the bed. I'm sure that what I'm seeing is the cab moving, but since I'm in the cab it appears to be the bed. Even given that, the potholes on my 'street' are probably close to a foot deep and don't induce anything that warrants even a raised eyebrow. On normal roads, there's virtually nothing.

I'd love to see a rational explanation for the supposed bed shake, because it makes no sense at all. I can't reproduce it no matter how hard I try. As I've said in numerous threads, my dirt road will test a suspension and frame. My Jeep Liberty will beat you to death, or eject you if not belted in, at 10 mph. I can drive the truck through there at 15-20 mph with a lot less drama. I haul my trash can to the bottom of the hill and the can will stand up without falling over. If the Liberty had a bed, the can would have been tossed out long before I got to the bottom.

So, someone enlighten me please. How exactly does this bed shake thingy work and how can I get mine to do it?

 

How stiff the frame is doesnt necessarily apply in this instance. He said that the bed was flexing from mid-wheel arch back to the tailgate. Being that the frame is so rigid, any bumps that arent absorbed by the suspension, could be showing up as flex in a lightweight or weakly designed bed.

Due to different bed lengths this may not be as much of an issue on the shorter bed SCrews, but will show up more with the 6.5' and 8' beds.

Hopefully we wont start to now see "bed side cracks" in the metal like the door cracks of the 97-03's...which was caused by a lightweight door design that was very prone to flexing.

As a side note I was behind an 04 F-150 the other day, it was on a somewhat rough stretch of road and I did notice some flex. I wouldnt say that it was bad, but certainly more than I was expecting. And no, it was not the cab that I saw moving in relation to the bed. It was as 04 RED LARIAT described, it flexed from the wheel well back.

 

Hey 04 Red Lariat? I know exactly what you're talking about. I witnessed it twice. Once while driving beside one down the road......it was really noticealbe. Not something that should be considered normal. Definately a defect for which I am sure will warrant a recall soon. The second time, believe it or not, was on Motor Trend TV when they were road testing an 04 Lariat. Sure enough, when the camera got beside the rolling truck, the bed was shaking on that one too. I wouldn't let it get you down though because it will definatley get Ford's attention if it hasn't already. Enjoy your new toy....after all, it does have a warranty.

 

Several of us have spoken out on this issue and many others don't seem to experience the problem. Until the above posts (the 1st ones to mention the 'wheel arch' scenario), I was beginning to disbelieve my own observations in my side view mirror, i.e. exaggerated flexing above and aft of the wheel arch. On my XLT Screw, the problem is worse at slow speeds, e.g. 20-30 mph, over small, sharp bumps. For example, driving slowly through a campus I encounter a series of ripples in the pavement caused by tree roots under the asphalt...the bed shakes abnormally and the wheel arch flexing can be noted. Conversely, over some potholes no problem is noted. A recent change of tires somewhat altered the harmonic frequency of the shake, but did not eliminate it.

FORD, LISTEN UP! There is a PROBLEM here. Earlier, somebody said a dealer passed on the word that a fix is under study. Hopefully, that wasn't just dealer's BS as a means of consoling the customer.

 

I picked up my FX/4 scab 2/7,,,6 1/2 ft bed,,,,have also noticed bed shake too,,,,,hummmmm????just might be cab moving ,since we`re part of the cab,,,,needs more info/observations,,can u say ,warranty,,,YES!!

 

Ok, I took a look under my bed and see the frame (which should be quite rigid) runs full length back to the bumper. The bed itself is supported on transverse beams at roughly 12" on center, that extend out near the outer edges of the bed. I don't see how that structure can flex, and mine sure doesn't regardless of what I drive over. It looks a lot less likely to flex, jiggle or shake than any other structure I've seen for a pickup bed. I can't imagine the transverse 2" box sections flexing in a 15" or less cantilever, especially with the bed acting as a structural diaphragm, tying them together.

Are you seeing the bed moving in relationship to the back bumper? If not, then I don't think it's the bed.

 

Somebody needs to whip out a digital camcorder and record this...then post a video on the net so we can see it

 

I just got my new digi cam yesterday.
I am going to take it with me and hopefully I will see that truck again I think I may know where to find it I saw it at a local accessories shop yesterday afternoon.
If I can locate the truck and the owner and he permits I will follow him and record this.

I was so shock by how much the bed was flexing I didnt even think to look at the bumper to see if it was moving or not.

 

I just went out and looked at the bed has anyone noticed there is no bed bolt in the center cross member the one in the center of the rear wheel i could not see the other rear ones to see if they have a bolt or not i am sure the back one dose this could be a problem or the cause of the bed shake as my Screw 4x4 dose this too. Just an observation.

 

KJB and those fortunate others who don't seem affected by the issue...I have never doubted the strength and torsional integrity of the '04 frame. Perhaps therein lies the problem. Perhaps my '90 and '97 never suffered the problem BECAUSE of the flexi-frames of those vehicles that flexed enough to absorb some of the suspension inputs. Perhaps the '04 frame is so rigid that mismatched suspension tuning, engineering, or design is an issue. Some refer to the problem as 'bed shake', but the shaking bed is just a singular manifestation of several other suspended parts ...my son and I noted that every suspended part (i.e. everything except wheels, axle, and lower shocks) of the rear has the shakes. This points the finger at suspension, not frame.

I stopped by the local Ford service dept. this afternoon...they said they never heard of the problem.

 

I have the FX4 Screw and have noticed the bed shake from day 1. I don't think the suspension, front or rear is tuned right. The thing I notice is in the front suspension. It always seems to have a slight after shake when hitting any bump. The truck seems smooth I think because of the weight of the truck. It just seems like the rebound rate is not quite right. As far as the bed shake, I don't know, but intend to investigate it further.