Have a 03 f350 with the 6.0 have been experiencing very harsh shaking problems. This only happens at highway speeds 55-60 any other speed is smooth as can be weather it's 25-95 mph. The weird part is that it only shakes when the truck shifts into overdrive and it shakes bad and if you lay into it like you were gonna pass someone it stops then shifts back into overdrive and shakes agains any help would be greatly appreciated

 

Have you tried to throwing it in neutral at the speed it's shaking? If it doesn't go away at that speed it's a tire or suspension related part.

Any codes?

 

Yes I have and it does stop or if you lift off the throttle also stops and no have not hooked it up to a computer yet but it just got new injectors and oil cooler and egr delete. But truck shook faintly before all that was done

 

Probably an injector.

 

Driveshaft slip joint, or U-joint. Change in behavior on throttle changes matches with changes in driveline geometry during power transients.

Slim chance it could be the pavement, and not the truck. Pay attention next time it happens and make sure you're not always at the same PLACE when it happens. Old asphalt pavement is particularly succeptible to this phenomenon.

-blaine

 

Same place same speed, it could just be. Driving back home one Friday I get this horrible vibration that's just like a loose front wheel close to falling off. Pull in to the next park place, stop, get out, look around, and think- I did the same thing right here 2 months ago as well. Not saying it is, but it could be...

 

Are you talking about bucking? Like as if it is more of an jerking front to back? If so, I've had that problem, but only while towing my fifth wheel trailer at 55 mph with steady foot on peddle with the accelerator in neutral position, not accelerating or decelerating. If I was driving faster or slower than 55mph, or accelerating or decelerating, it wouldn't do it. It also didn't do it at 55 if I was in cruise control. The dealership couldn't figure it out, eventually telling me that it was my foot... WHAT?!!!

Anyway, I finally got it to settle down with a custom tow tune from Gearhead Automotive. It doesn't do it as easily now since I loaded that tow tune. Actually, I'm not sure it does it anymore at all as I haven't noticed it since the latest update to the tune code. One of the things the dealer tried was to unplug my EGR, so maybe you could try that on your's, ya never know. Your issue sounds strikingly like mine, except mine was only while towing the fifth wheel trailer. I'd be interested in hearing what your issue turns out to be. It would be nice if your diagnosis helps narrow down my issue some. I hope this helps your search.