Early Onset Death Wobble Help

[spurly]

2 hour drive from Omaha to Des Moines last night and the steering was perfect. A little windy so it was all over the place but no wobble or shimmy on the interstate or in town, but so far so good.

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[TJ_HOOKER]

So here’s my similar experience and what I found to be the issue.

first off, my setup:
2021 JLUR Ecodiesel
Teraflex spacer lift with shock extensions
JT Rubicon Fox shocks
Fox stabilizer 2.0 Performance Series
Adjustable front and rear trac bars
37x12.50x17 on alum wheels

So after I went to 37’s this week I experienced exactly what the original post described. It was like DW was imminent but didn’t quite happen. I’ve rechecked anything I have installed and all seems tight and where I left it. I thought maybe caster angle, and even tho it isn’t suggested in the teraflex kit I looked into longer lower front control arms. I went with the mopar ones found in the 2.5” kit as they were cheap, avail overnight and there must be a reason why they use them in their kit so I figure why not. I stalled them, torqued to spec, and went for a drive. No joy. In fact, it almost felt worse.

I rechecked everything again and was leaning towards ball joints at this point as from what I read some people had issues in the earlier JL’s with them. But, for a quick test I decided to put my OEM steering stabilizer back on. Took it for the exact same drive and the problem was gone. No matter how hard I tried I could not produce the same wobble. Did my usual 100km commute to work this morning and zero issues.

So here’s what I found. When I was reinstalling the OEM stabilizer the steering side bracket had bent inward as the fox unit must have a shorter bushing and sleeve. I had to bend the bottom side down to get the OEM bushing and sleeve in and get the bolt through. Not a big deal and not the first time I’ve seen that with any kind of shock. The bigger issue tho was that the OEM bolt which fox says to reuse is a carriage bolt and the squared bit presses in to the fox sleeve and deforms it a bit (pic below). I figure this is where the problem lies. It’s either that or the heim joint at the axle side bracket is shot but it doesn’t appear to be, it pivots as it should and by hand I can’t get any side to side movement. The stabilizer itself seems fine, it takes some serious force to move it in and out by hand where the OEM one is easier to do. This fox unit came to me used, but maybe a year old.

I contacted fox tech support and while they are puzzled by the carriage bolt doing what it did, they still consider bushings “wear items” and would not warranty them. I have the part numbers for the bushing, sleeve and heim and have them on order, they were like $9/each for the bushing and sleeve and $40 for the heim so not a huge deal.

Anyhow, thought I’d share.

 

[Jeep&dogs]

So here’s my similar experience and what I found to be the issue.

first off, my setup:
2021 JLUR Ecodiesel
Teraflex spacer lift with shock extensions
JT Rubicon Fox shocks
Fox stabilizer 2.0 Performance Series
Adjustable front and rear trac bars
37x12.50x17 on alum wheels

So after I went to 37’s this week I experienced exactly what the original post described. It was like DW was imminent but didn’t quite happen. I’ve rechecked anything I have installed and all seems tight and where I left it. I thought maybe caster angle, and even tho it isn’t suggested in the teraflex kit I looked into longer lower front control arms. I went with the mopar ones found in the 2.5” kit as they were cheap, avail overnight and there must be a reason why they use them in their kit so I figure why not. I stalled them, torqued to spec, and went for a drive. No joy. In fact, it almost felt worse.

I rechecked everything again and was leaning towards ball joints at this point as from what I read some people had issues in the earlier JL’s with them. But, for a quick test I decided to put my OEM steering stabilizer back on. Took it for the exact same drive and the problem was gone. No matter how hard I tried I could not produce the same wobble. Did my usual 100km commute to work this morning and zero issues.

So here’s what I found. When I was reinstalling the OEM stabilizer the steering side bracket had bent inward as the fox unit must have a shorter bushing and sleeve. I had to bend the bottom side down to get the OEM bushing and sleeve in and get the bolt through. Not a big deal and not the first time I’ve seen that with any kind of shock. The bigger issue tho was that the OEM bolt which fox says to reuse is a carriage bolt and the squared bit presses in to the fox sleeve and deforms it a bit (pic below). I figure this is where the problem lies. It’s either that or the heim joint at the axle side bracket is shot but it doesn’t appear to be, it pivots as it should and by hand I can’t get any side to side movement. The stabilizer itself seems fine, it takes some serious force to move it in and out by hand where the OEM one is easier to do. This fox unit came to me used, but maybe a year old.

I contacted fox tech support and while they are puzzled by the carriage bolt doing what it did, they still consider bushings “wear items” and would not warranty them. I have the part numbers for the bushing, sleeve and heim and have them on order, they were like $9/each for the bushing and sleeve and $40 for the heim so not a huge deal.

Anyhow, thought I’d share.

There has been a few instances where the stock stabilizer corrected the issues. MC has actually taken theirs off the site and recommended using the factory one. I honestly don’t think the stabilizer was moving at all, I think there is some harmonics in the Jl and the dampening force needs to be “just right” too much and it causes issues and too little does.

 

[TJ_HOOKER]

There has been a few instances where the stock stabilizer corrected the issues. MC has actually taken theirs off the site and recommended using the factory one. I honestly don’t think the stabilizer was moving at all, I think there is some harmonics in the Jl and the dampening force needs to be “just right” too much and it causes issues and too little does.

Interesting. I’ll have to see how this plays out after I replace the parts on the Fox unit I have. The sleeve is definitely deformed a bit though.

 

[Mtenna99]

The 2.5 spacer lift I put on is giving me some strong shimming whenever I hit bumps on the highway with the stock 32. This lift was only temporary to fit 37 and will be installing the MC game changer. I have a trip coming up and I want to throw the 37 on before but not sure if they will make it worse and I should wait till after…decisions.

 

[gato]

Well I'm reviving my old thread because I'm still facing the same issues I was a year ago. Maybe even worse now since I threw on beadlocks. With my new wheels coming in 44 pounds each, I'm sure that isn't helping my situation. Over the last year it was tolerable and I never experienced full on death wobble. Even after a handful of trips to Colorado and Moab it never seemed to get worse.

I've also noticed that I can feel every little bump and crack in the road through my steering wheel.

I think my next step is replacing the balljoints with Dynatrac HD Rebuildable ball joints. I've put it off for this long because I didn't want to spend the money.

I got to thinking too, is there any chance that my Synergy Track Bar could be bad?

OP. I have the same lift/set up as you have Mopar + 0.75" spacer, Synergy relocation bracket, 37s, etc.

In my case the shimmy and 2 instances of full on DW at ~35-40MPH were fixed by tightening the tierod ball joints (after trying everything). I think they work themselves slightly loose over time due to the aluminum knuckles. (I did also slightly tighten the drag link on the knuckle side, but don't think that mattered).

After about a month I started getting shimmy again, and sure enough slightly tightening the tierod ball joint nuts fixed it.

I have a theory. The Synergy relocation bracket cause downward pressure on the tierod when you turn full passenger (it also makes it harder to turn full passenger than full driver). I think over time this causes the tierod to loosen a bit.

I actually remove the steering stabilizer, and while I obviously got a bit more bump steer it never ever went into shimmy or any incipient DW oscilation.

For the benefit of others I found out that with the factory stabilizer I only had shimmy at highway speeds when hitting expansion joints and such, but never in town. With a stiffer stabilizer (Teraflex) it was fine at highway speeds but shimmying at ~30-40MPH. So I think the stiffness of the stabilizer simply moves the issue to a different speed range (resonating frequency).

Hope this helps. Pressing in new ball joints is not something I feel I can tackle, so I'm avoiding that, even though my ball joints drive me crazy with the clicking noise.

 

[roaniecowpony]

...

For the benefit of others I found out that with the factory stabilizer I only had shimmy at highway speeds when hitting expansion joints and such, but never in town. With a stiffer stabilizer (Teraflex) it was fine at highway speeds but shimmying at ~30-40MPH. So I think the stiffness of the stabilizer simply moves the issue to a different speed range (resonating frequency).

...

I agree with your conclusion about the different stabilizers (dampers). But, higher stiffness (of the overall system) pushes the resonant frequency higher. I don't think we're dealing with second resonance phases. So, I'm suspicious that something is going on that you haven't discovered with this installation of the new damper or something loosened. If the damper had less stiffness in the mounting or less damping in the reversal of direction zone than the factory, that would be an explanation. So, another round of checking torque on ALL the steering system and especially the trackbar and stabilizer would be a start. If nothing stands out, then focus on the mounting of the stabilizer (bolt to bushing diameters, clamping, and finally the bushings themselves. What trackbar do you have?

 

[gato]

If nothing stands out, then focus on the mounting of the stabilizer (bolt to bushing diameters, clamping, and finally the bushings themselves. What trackbar do you have?

That is the one area that gives me pause. First, for both stabilizers (factory and Teraflex 9550) I had to drill out one end of the bushing to fit the stupid 1/2" Synergy reallocation bracket mounting bolt. Both of them had some heat damage to the bushings (I'm just not patient enough to drill slowly - what a pain that was). Synergy has all these hacks for the JL, like this 1/2" bolt and the hack with the tierod length for the Rubicon. They don't want to do product specific parts like everyone else. /rant

Second is that as you turn the wheel full passenger there is bending load being put on the trackbar stabilizer mounting bold and the tierod. The loads are totally in line/parallel with the tie rod.

I tried to order a TS Fox stabilizer but it has been backordered forever.

I did try to drive without a stabilizer and didn't get any death wobble, but did get normal bump steer shimmy. So, my setup can not be too far off. I think this Synergy relocation system is moare of a problem than a solution.

 

[spinxt]

UPDATE: I found a significant amount of play in the knuckle end of the drag link. Could this be causing my issue? I can physically grab the drag link and feel and hear play in the joint.

 

[Spencer]

UPDATE: I found a significant amount of play in the knuckle end of the drag link. Could this be causing my issue? I can physically grab the drag link and feel and hear play in the joint.

IMO any play in the steering components can cause wobbles

 

[GrayWolf.Overland]

Go in for an alignment. Axles centered, toe dialed in and caster adjusted to > 5 degrees on both sides

 

[Spencer]

Go in for an alignment. Axles centered, toe dialed in and caster adjusted to > 5 degrees on both sides

Factory specs for caster are 4.8*
I have tried everything from 5* up to 8*
Yes, higher caster helps calm things down and drive straight. The problem is the front driveshaft isn’t happy with the higher caster settings.

I was getting crazy harmonic vibrations from the front driveshaft at 7.5* caster. Recently I dropped it back down to factory specs of 4.8* and it’s driving fine and I’m able to use 4HI on the snowy icy roads without any harmonic vibrations.

Give and take, pros and cons. Your choice.

 

[grandsrus]

Go in for an alignment. Axles centered, toe dialed in and caster adjusted to > 5 degrees on both sides

What was toe at?

 

[GrayWolf.Overland]

Factory specs for caster are 4.8*
I have tried everything from 5* up to 8*
Yes, higher caster helps calm things down and drive straight. The problem is the front driveshaft isn’t happy with the higher caster settings.

I was getting crazy harmonic vibrations from the front driveshaft at 7.5* caster. Recently I dropped it back down to factory specs of 4.8* and it’s driving fine and I’m able to use 4HI on the snowy icy roads without any harmonic vibrations.

Give and take, pros and cons. Your choice.

Greater than 5 shouldn't mean 6
5.1 to 5.5 worked best for me. The best setting also varies by lift height..i might be wrong on that.

Keep it where you troubles stop, even if the ride quality is slightly wandery. It's a Jeep thing after all

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