Uncontrollable sway on highway

I had an interesting experience yesterday and was hoping someone may have some insight.

I was coming home from watching a rockcrawling competition yesterday (I did not compete so not a broken part) and tentatively let my 21 year old sister in law drive.

We were coming down a mountain pass and I was in the back looking at my phone. All of a sudden it felt like she was doing some slalom movement. Briefly I chalked it up to her maybe over-correcting steering or goofing off but it started to ampilify back and forth. I yelled what are you doing and she yelled nothing! and took her hands off the steering it continued to steer back and forth harder with the stability control screaming at her.

I yelled Brake! Brake! Brake! Brake! as it felt like an inevitable roll if it kept going.

We came to a stop and I checked for any obvious breaks, loose or damaged steering front and back. Nothing. I drove it home going up to 80 mph through the mountain for the next 4 hours. No issues.

I know its not the easiest to drive on the freeway especially curvy roads as its got play and can be very sensitive to over correcting so I am chalking it up to inexperience and touchy steering. Its not that death wobble. I have seen the videos of that and it was not a shaking; Were talking full on high speed slalom.

Its almost as if it was over correcting itself. She may have started it off but it just seemed to amplify on its own.

Anyone seen a similar problem?

Possible Relevant Mods.
Dealer Installed 3 Inch Fabtech Coil Lift.
35 inch MT on 17X10 Weld Rims
JKS Quicker Disconnects
EVO C Gussets
MetalCloak Adjustable TracBar
Artec Heavy Duty Track Bar Bracket Front
Artec Axle Truss Front
Custom Front Long Travel Shock Install with Ford Shock Towers
13 Inch Travel Front Rancho 9000 Shocks (Set to 1 for soft ride)
Custom .25 Inch Rear Tracbar bracket. (Ripped old off on trail)

Other unlikely but possible affecting mod
ARB Locker Front and Rear
Superchips 3872 Flashpaq

Note. I have bent my Drag Link (Couple times) and Tie Rod. They have been straightened but in process of researching and buying replacements.
I also ripped off the old rear tracbar a few weeks back and replaced the axle side mount.
I still have stock control arms and they too are on my short list for replacing after drive shaft.

I will do a check on the ball joints as that is on my list of possible contributors.
Ill check bushing on my stock arms also.

After talking more with my sister in law she admitted to having started the process when she over corrected from a gust or groove in the road but am just covering my bases. I do not feel like it drives any different with any of my mods except a little softer and a touch more roll since I added the long shocks (set to 1) and taller mount towers.
It was quite the adrenaline pumping experience and do not wish to go through it again.

Maybe you can tell us a bit about your Jeep and what all you have installed on it.

That's crazy. I've never heard of anything like that. Definitely knowing what you've installed would help figure it out.

Seams you've experienced some version of death wobble. Knowing what you have will help.

My wild ass guess: grooves in the road pulling your tires around, she steers, traction control gets involved, makes matters worse. Sounds scary though.

How old are your ball joints? Maybe slowly wearing out and you've gotten used to them? Do you have a lift?

wayoflife said:

Maybe you can tell us a bit about your Jeep and what all you have installed on it.

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I'm interested in knowing the build date of your jeep, if you could provide that.

Sounds like the new shocks are a little too soft for windy mountain highway driving.

Robot_Guy said:

I'm interested in knowing the build date of your jeep, if you could provide that.

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Uhhhhhhhh........

cozdude said:

Uhhhhhhhh........

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Where is the badass guy?

Not sure I would have gone to speeds up to 80 after that knowing your tie rod and drag link are bent, I must really be getting old

A buddy of mine had the exact same feel, I test drove it and instantly felt out of control. We found it was a loose sway bar link bolt in the rear. It literally felt like we were going to flip over if we took a corner faster than 3mph. Since you checked steering ect. probably not the case but was a really bad feeling and similar to what you describe.

cozdude said:

Uhhhhhhhh........

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Is there a problem with that question??


I have had similar complaints of what the OP is talking about. Check the front sway bar bracket mounted to the frame rail. There is a possibility that the weld has broke from the top of the bracket; and the bracket is moving while driving down the road.

Robot_Guy said:

Is there a problem with that question??


I have had similar complaints of what the OP is talking about. Check the front sway bar bracket mounted to the frame rail. There is a possibility that the weld has broke from the top of the bracket; and the bracket is moving while driving down the road.

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Where you asking Wayolife or the OP?

boardsurfer said:

My wild ass guess: grooves in the road pulling your tires around, she steers, traction control gets involved, makes matters worse. Sounds scary though.

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I had something similar happen this past weekend in the Smokies. The roads are very steep and we were headed downhill. There was a lane shift due to construction and I came in too hot. We changed pavement from old to new on a turn and the left side compressed, then released as the right compressed. It was like a weird waterbed feeling after the rear end followed suit. I'd say it repeated 3 or 4 times until I slowed down ~10mph. My jeep was heavily loaded with camping gear, but I'd imagine 3-4 people would set you up about the same. It wasn't death wobble, but it freaked me out.

Mine was just a fluke, hopefully yours was too. Glad you made it OK.

I liked the part about the vehicle swaying all over about to lose it and she takes her hands off the wheel.

I dont think I would be letting her drive my rig again anytime soon.

dagdag said:

Sounds like the new shocks are a little too soft for windy mountain highway driving.

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This was my suggestion when I read the selection of softness for the shocks. I went from a hard to soft shock for about a week, and the handling characteristics of the Jeep changed significantly. I did some driving in the Texas Hill Country with the soft shock, and I was certain that I would lose the Jeep a couple of times.

I have not found any other problems to this point. I firmed up the shocks and will see how that handles.

SEAJ said:

I have not found any other problems to this point. I firmed up the shocks and will see how that handles.

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Adjustable shocks. Nice!

You may want to check your ball joints and TREs for any up and down movement. While I didn't have an incident like yours (I live in the midwest with a lot of straight flat roads), I did have a significant amount of play in my steering wheel that made me fearful of death wobble or something similar to your case. replacing the drag link, tie rod, and ball joints really helped.