Good afternoon all,
I have read just about every thread on the shaking and what could cause it. And I have done everything.
So let me give you the back story:

2004 F-250 Lariat, 6.0 SRW 4X4 bought used in 2017.
I bought it for the soul purpose at the time for towing our camper. My F-150 was my daily commuter.
Well my son fell in love with the F-150 and he bought it off me and the 250 became the daily commuter.

This is what I have replaced on it so far:
Tie Rods, Front and rear shocks, tires, Front wheel bearings, front sway bar and linkage, carrier bearing, all U-Joints, fuel pump, #8 fuel injector, upper and lower ball joints, differential cover.

The trucks was not "bullet proofed" but it was dealer proofed. Bolts were removed and studs added.

So I took the truck in because it was shaking. Mechanic says the tie rods. Tie rods get replaced. Then he says the carrier bearing is loose. Which I knew, so that was replaced. This was all last Friday.

So this what the shake is:
Between 40 and 50 mph the truck bounces. (Harmonic issue with the frame???)
But after 55 mph and all the way up to 110 mph the truck shakes violently. This isn't a wobble and it is not felt in the steering wheel. You can feel it in your seat on both sides and the back seat.
I checked under the truck and the every thing is tight. The truck doesn't shake quite as bad in the morning, but it does shake.

So I am down to two things that I can think of. Rear sway bar and linkage or the drive shaft needs to be balanced.
I did not do the repairs myself. Always took it to a mechanic. So I can not answer if everything with the driveshaft was replaced the same way it came out.

Am I missing anything? And please ask all the questions that might help. The Ford mechanic and my diesel mechanic are at a loss as to why it shakes.

Thanks,
J

 

Welcome to FTE.

Start with getting the tires balanced by a competent tire shop. It sounds like you have some level of death wobble...

 

I will have that done today. But I failed to mention I did replace the steering stabilizer. Could warped rotors cause the same thing?
One thing I noticed today on my hour drive in was the shaking happens in intervals. It will be 3 seconds of smooth driving and 4 seconds of shaking. To me this sounds a lot like a imbalance in the drive shaft but it could be the wheels as well.

I will let you know when it is done if it fixes anything. I am going to have them balance and rotate the tires.

Thanks
J

 

Sounds like a bent driveshaft or one that wasn't marked when the U-joints were replaced.

 

Sorry for the long wait. But the problem was resolved this past weekend. Turns out it was a duel issue. The passenger front tire had separated belts and a long bubble on the inside of the tire. And the shocks were gone.

Heres the strange part. The tires and shocks are less than a year old. I do a lot of towing but I would expect more from rancho shocks and nitro tires.

But none the less it is fixed and drives better than it did when I bought it.

Thanks for the help

j