Odd death wobble issue.

[82355]

My 1988 V10 Suburban has a Dana 44 from a 1975 K20 under the front of it. It needs ball joints, not badly, but they are due to be replaced. I use to have 35x12.50x16.5" BFG Mud Terrains on it. I blew one out, so I swapped to a set of 37x12.50x16.5 Goodyear Hummer take offs. I never had any death wobble issues before the tire swap. After the tire swap it was almost undriveable.

That being said, I had slammed into something and bent the tie rod pretty bad, and destroyed the steering stabilizer. The tie rod ends were COMPLETELY shot anyway, so I swapped on a different tie rod with good ends that I had sitting around. The only problem is that it is for the wrong year, so I can't use the steering stabilizer with it. I already ordered an aftermarket clamp on steering stabilizer mount for the tie rod, so that should take car of that.

When I swapped on the new tire rod, it took care of MOST of the death wobble. I am guessing new ball joints would take care of the rest of it. The odd issue is that it only death wobbles between 35-45mph, and only on pavement (it is also intermittent, it doesn't always death wobble). It will not death wobble on gravel. I found that quite odd, and was wondering if anyone else had experienced that before. Even stranger yet is that it has snowed here, so driving on snow pack doesn't change anything. Snow pack on gravel, no death wobble. Snow pack on pavement, intermittent death wobble. How does the road surface have any bearing on it, if it is covered in snow pack???

Martin

 

[Hogback Fabrication]

ANY loose component can cause it, start with the ball joints which you need anyway.

The stabilizer may tame it and tire balance may be an issue as well since that's the change that started all of this.

 

[82355]

Yeah, I'm not looking for suggestions. I am confident balancing the tires, and replacing the ball joints will take care of it. I just thought it was odd that it only happens on pavement, with or without snow pack.

Martin

 

[82355]

That sounded kind of dick-ish. I guess I should have said thanks for the advice anyway.

Martin

 

[Hogback Fabrication]

That sounded kind of dick-ish. I guess I should have said thanks for the advice anyway.

Martin

No problem, I took it as "do you think this might fix this" rather than "I'm pretty sure I know the problem but thought this is odd".

As far as what triggers death wobble, it completely varies. The whole problem is a harmonic deal that really can be set off by any kind of bump in the road, very common for asphalt to set it off.

Who knows why dirt roads don't set it off for you but regardless, you know how to fix it

 

[Fordum]

Actually the road surface thing makes sense. When the tires are rolling on dry pavement, they have about the least amount of surface area touching.
It is easy for them to change direction in a wobble.

When you are on dirt, they sink into it to a greater or lesser amount depending on how hard it is.
The lugs on the tire grip the dirt, and tend to make changing directions suddenly more difficult.
When it twists on pavement, the tips of the lugs just slide across, but on dirt, they have to push the dirt aside to move.

Its not a lot of difference, but if you are right on the edge, its enough to make the difference between DW and no DW.

We used to tow my old Jeep between the places we want to use it. On the pavement, no problem. It would track perfectly and follow the tow car around curves and turns.

As soon as we hit dirt, I had to get out and drive it. Otherwise, sooner or later, we would try to go around a curve and it would try to go straight.

You would think that the dirt would tend to pull the wheels around better, but it didn't.

 

[82355]

That doesn't take into account the snow pack, but then again, being in Florida you probably are a little short on experience with snow . . . . .

Martin

 

[Fordum]

That doesn't take into account the snow pack, but then again, being in Florida you probably are a little short on experience with snow . . . . .

Martin

Very true, but I figure that the snow on pavement is just easier to change directions, the gravel lets the tire sink in like dirt, and thick snow pack is just too soft and light to stop the wobble.

But, the only snow I see is in cones........

 

[Bigrigr]

I tend to come at this from a different angle, I have quite a bit of alignment experience in my past life, and i wonder about the alignment being out because of the bent tie rod and tie rod end change. Did you have it aligned after you swapped the TRE's? If not, the alignment is definately out...... If the "toe" angle is way off, it will cause the tires to slide down the road, rather than roll, causing bad tire wear and all sorts of handling issues. The pavement cause the wobble more, because of the resistance to the tires "Sliding", in the dirt the tires have less resistance. Just like when you try to turn on pavement in 4wheel.

P.S. The ball joints being loose will only aggrevate the problem, and prevent you from keeping the truck in alignment as well. They must be replaced before you have an alignment done. JMO

 

[82355]

The alignment was out with the bent tie rod as well as with the "new" tie rod. The issue was the same before and after. It just wasn't as bad after installing the other tie rod.

I balanced the tires last night, and the front tires were horribly out of balanced. It still does it (though once again, not as bad as before). The crazy thing is that there was absolutely zero death wobble with the unbalanced 35x12.50x16.5" BFG's that were on it before these Hummer take offs.

Martin

 

[Fancy]

Fordum and 38377k5 are actually pretty close. It is indeed a harmonic balance or frequency type situation and it is different for every body as dependent on the components involved. A "Death Wobble" as it is called is unstable frequency at which your truck with shake due to loose components or unaligned ect. This is why it only happens under certain condition or speeds, without getting super technical or detailed. On the dirt it is alot harder (if not impossible, depending on components involved) for your truck to find that frequency or "Wobble" with out it being counter acted by something. Where as on the pavement (even with snow) it is a lot easier partially do to less contact yes.

I can try to get more detailed if need but but i am super tired and it get way complicating but hope this help. The important thing is that you know how to fix it! Good luck!

 

[British Slave]

http://www.4x4training.com/Articles/VehicleRepair/DeathWobble.html

 

[82355]

Installed a Rancho generic tie rod steering stabilizer mount so I could hook up my stabilizer, death wobble = gone.

Martin

 

[63chevyll]

Hey Martin,

The way I read your above statement, it sounds like you just put the mount on and not the stabilizer and it fixed your problem.

 

[DickeysK5]

Glad to hear you solved the problem!? When I switched from original design MTRs to the new MTRs w/kevlar, my Blazer developed death wobble. When I checked the alignment, it was way off In my situation, tires and alignment made the difference between no wobble and bad wobble.

 

[Fancy]

Just so you know a steering stabilizer can never fix death wobble as it is never the cause of death wobble it can only mask it or what most refer to band aiding it. If your happy with it though then by all means do as you wish. I am just simply stating that depending on what the issue was it will only continue to wear or remain unresolved.

I hope im not raining on the parade i just went through the same problem and want to share my knowledge and experience on a subject that is extremely confusing to most.

 

[82355]

Hey Martin,

The way I read your above statement, it sounds like you just put the mount on and not the stabilizer and it fixed your problem.

I had installed a used tie rod from a different year front axle than the axle under the Suburban. It had the steering stabilizer hole on the outside end of the tie rod instead of the center. The tie rod that came off the axle had the steering stabilizer hole in the middle of the tie rod. So I couldn't hook up a steering stabilizer. I bought a generic Rancho steering stabilizer mount, and used the tie rod mount so that I could hook up both ends of the steering stabilizer. Does that make sense, or do I need to take some pictures?

Martin

 

[82355]

Just so you know a steering stabilizer can never fix death wobble as it is never the cause of death wobble it can only mask it or what most refer to band aiding it. If your happy with it though then by all means do as you wish. I am just simply stating that depending on what the issue was it will only continue to wear or remain unresolved.

I hope im not raining on the parade i just went through the same problem and want to share my knowledge and experience on a subject that is extremely confusing to most.

No rain on my parade. I am well aware of what I did. Although I still maintain that a steering stabilizer can fix death wobble. It is a factory installed part, and if it is worn, and you have death wobble, you replace it, much like any other worn OEM part. That being said, I KNOW that I have bad ball joints. Really bad ball joints. I know they need replaced, but I am in no big hurry to get to it, and for now, making it so that the "factory" steering stabilizer can be used, fixes the problem.

Martin