the truck wasn't mine, but..we were driving into San Antonio this morning and was coming up on a modern super duty crew cab fx4 long bed. before we passed it the truck started shaking violently, seeming to come from the front. we were on a six lane and traffic was running 70 or so. I backed off as did others to let the driver get it safely to the shoulder.
my question is what was the likely culprit.
honestly I have never seen a vehicle shaking so much.

 

Death wobble......

 

Google death wobble.

 

Weath Dobble

 

As others said, death wobble...caused by loose steering parts, out of balance tires, bad alignment, could be multiple things or just one...

 

I’d say either death wobble or the driver was having a seizure!

 

I always wondered what death wobble looked like to others on the road.

 

“Wild Shaking” this is NOT what I thought this thread was about...

 

Factory track bar bushing is the cause.

I have 285s and no stabilizer. Never a problem. My ICON track bar has a Heim joint. Works awesome.

 

From my point of view it was bizarre. It looked like the frame of the truck was twisting from all of the shaking.
I did read one article and it suggested the "death wobble" is limited to 4x4/fx4 super duties.
But this wobble is not an issue for us F150 sorts?
Just started thinking of an Eddie Money song - "shakin".

 

Death wobble can happen to anything with a solid front axle, whereas current F150s use independent front axles with control arms which makes it mostly a non-issue. Jeep forums are full of guys trying to figure out how to mitigate the issue on their modified rigs. The particular design of the 05+ Super Dutys with coil springs seems to be very prone to death wobble. I have a pile of solid front axle F350s (2 '89s, a '94, and an 03) in the yard and have never suffered this with any of them, even when they were in states of heavy neglect and disrepair.

Also, there are many accounts on this forum, and elsewhere, of guys suffering death wobble before you would even schedule your first oil change. I personally had it happen when my friend and I test drove a '19 F350 with less than 100 miles on it and hit a joint in a bridge. I didn't end up buying at that time, but my friend ordered a '19 and suffered the same fate before 5000 miles. It doesn't seem to be an issue limited to poor maintenance on these trucks. It seems to be an inherent issue with the geometry of the front suspension, the caster angle, and the lack of rigidity in the track bar and bracket. It seems that anyone that has used an aftermarket track bar or caster bushing has totally mitigated this issue. Ford's band-aid fix is to replace the steering stabilizer with an updated one and hope that it lasts long enough for your warranty to run out so that it's your issue and not theirs, but again there are many accounts of this fixing nothing, because it does not address the root cause.

 

Coil sprung solid axles are very prone to the death wobble. Jeep, Dodge/Ram, and the SuperDuty all suffer from it. The radius arms & track bar are added points of contact that have to be at the correct geometry, with no loose tolerances (worn bushings). Caster angle is also a factor, which is on the light side on these trucks. I had a '78 F150 that developed a bad DW not long after I bought it (coil sprung, radius arm/track bar setup). I replaced the bushings in the track bar and all was well again.

I miss leaf springs. They didn't suffer from the DW issue.