With no satisfactory answers from Ford or Ford dealerships, this engineer explains what’s happening during a death wobble.
A recent video posted on Reddit showing a fairly new Ford F-350 experiencing what’s commonly known as a death wobble sparked a lively discussion with hundreds of comments. One comment in particular, from an engineer, received lots of upvotes for getting to the core of the matter, resonate frequencies to be more specific.
Redditor Doug910 succinctly explains how the death wobble plagues many vehicles, new and old, with solid front axles, and offers a plausible explanation that explains why Ford and Ford dealerships are finding it hard to diagnose and fix.
First, here’s the video that sparked interest on /r/cars and then here’s Doug’s explanation embedded below.
“Engineer here, and pretty knowledgeable about the the “death wobble” and thought I would share some knowledge.
Contrary to popular belief, the death wobble is not anything like a “tank slapper” you would get on a motorcycle. Yes, it’s scary, but it’s not a dynamically unstable event that will make you start swerving around the highway. During the wobble, the vehicle violently shakes, but tracks straight. Gradually slowing down (with the brakes), will guarantee the wobble to go away.
Death wobble is simply an inherent issue with solid axle front suspension. A right sized bump at the right speed will send an input into the axle that is around the resonating frequency of the whole SFA system. Once the axle starts to resonate, there’s nothing you can do stop it, unless you reduce the frequency to take it out of resonance (i.e. slowing down).
The amplitude at which the death wobble vibrates at is directly related to the amount of play in the SFA system. That is why you see it more often in older Jeeps and trucks: more worn parts = more play in the system. It is much less common in new trucks since all the bushings and joints are still tight, but it can still happen depending on whether you got a bad part, or just bad luck with hitting the right kind of bump to induce resonance.
The steering damper will not prevent death wobble. It can only help decay the wobble once it is induced. Of course, all dampers still have their limits, so throwing dampers at the SFA will not fix the issue. In order to fix death wobble (or at least minimize the issue as much as possible), you need to figure out where the play is in the system AND THEN upgrade your steering damper.
I’m not sure what the dealer “fixes” are for all the manufacturers with SFAs, but I hope this info can help you should you, or know someone, have this issue so that you can take the proper steps to get it fixed! “
In the video we can see a Ford F-350 driving along on a road as good as any other American highway, straight, without too many bumps, and smooth enough. Then, out of nowhere, this Ford F-350 steering wheel starts to violently shake, sending vibrations and shock waves through the passenger compartment. According to the driver, once the shaking starts, there’s little he can do but to slow down safely and quickly.
Hop onto the NHTSA’s website and there are hundreds of complaints from Ford F-250 and F-350 owners from model years 2005-2019 with similar, if not the same experiences.
“I have a 2017 ford f250 that has what appears to be a common problem with superduty trucks. At highway speed if you hit a bump the front end/suspension will begin to shake violently. The only way to correct this is to slow way down and eventually it will stop shaking. Ford added a steering damper and i had to purchase tires to supposedly correct this problem. Ford dealer also stated i needed an additional alignment to further correct. This is a serious safety issue that Ford needs to correct immediately. If the truck needs an alignment to different specifications, ford should issue a recall and do the alignment.“
“Wright is with the McCune Wright Arevalo LLP law firm representing the plaintiffs in the Class Action, which claims that Ford knew about the alleged defect and despite the more than 1,200 complaints to NHTSA, has not issued a recall.”
It seems like the death wobble can be remedied, as evidenced by the handful of F-series owners in that Reddit thread who’ve had some luck with tire balances, alignment, damper installations, and self-inspections. But, for the vast majority of F-250 and F-350 owners, they’ve run out of fixes with the problem still present.
Hopefully, this lawsuit will accelerate and motivate Ford’s brightest and best to fix this issue at the factory and provide recall recourse for current Super Duty owners.
What good is a $40,000+ truck if you can’t reliably drive it or do any actual work with it?