Suggestions on fixing death wobble?

[JEEPCJTJ]

My DW didn't stop when I put on a new track bar or when the 1/2" (or so) toe in was corrected. It did stop when I got rid of these 17" wheels even though the tires were balanced well.


These are what replaced those.


And here is what made me think my DW was still available when pushed to the limit. I really thought the unbalancedness was just opening the door to the DW but luckily that wasn't the case, a little faster or a little slower made everything fine.

 

[Yendra Built]

The structure overall is poorly designed on the Wrangler, I have a 2004 TJ with a 2.4 and automatic and it has been a serious problem with this vehicle, I think because of being lighter. On ours new tires will fix it every time (our vehicle). Death wobble is not a one thing situation. I am converting to a 4.0 and acquired a 2005 crashed TJ with complete drive train electronics and the body removed, this gave me a good view of how these things are built.

I have always felt that serious death wobble to me shook everything, I couldn't read the speedometer when shaking so bad. The the spring towers are on the frame near the engine mounts and there is no crossmenber anywhere near, and the engine is mounted on rubber bushings able to flex. The only crossmembers are the round tube all the way to the front and the transmission support/skid plate.

It is common practice on high performance cars to connect the shock towers with a brace, and these cars have good structure already. The TJ frame is a light box structure that is able to act like 2 torsion bars and flex with the engine hung in between them. Many times it starts with the bump or a series of things (there was a spot on one road that always got it going) that get the oscillations going through the track bar and suspension and then all hell breaks loose.

I owned a 91 Land Cruiser 80 series, solid front axle and coil springs, there's no way for death wobble to go rampent in that thing. It was structurally very strong, even having a tube crossmember at the track bar mount. I have to build engine mounts for the 4.0 and will design them to make the frame stiffer through the spring tower area and engine mounts.

Well, that's my rant on death wobble for what its worth,,,,,,,,,,,,,

 

[astjp2]

Frame flex is not the problem IMHO, I would be more inclined on how the geometry is designed to mount the front axle, that track bar designed was used on 1 ton dodge trucks, (their frames dont flex) and they still get death wobble.

If you wanted to truly get rid of death wobble, a watts link on the front with non flex bushings or a trianglulated 4 link will do the same thing.

 

[Yendra Built]

I have more pictures to put up to show the frame structure and why I feel the flex contributes to death wobble. I feel from what I have experienced that its more than just suspension in the case of the Wranglers death wobble. Just ahead of the spring and shock tower is the frame mount for the track bar. This mount extends far enough below the frame to give the track bar a lever to torque the frame into oscillating with the assistance of the coil spring. I really think that a tube cross member from the track bar mount to the opposite side (like the 80 series Land Cruiser) might be a easy try for someone who is currently battling death wobble.

And why do some Wranglers never experience death wobble?
I will post more pictures when I get a chance.

 

[astjp2]

Well it sounds like to me that your stress analysis program is telling you to buy a Land Cruiser...

 

[Twopoint]

Just told the missus we would be in the garage for awhile in the AM. The more I get from y'all it looks like I have a vibration problem and not the death Wobble. Actually pretty happy about that .

if you have death wobble, there is no doubt in your mind,
and you will have to pull the driver seat out of your butt

 

[Yendra Built]

Ok so I sold the Land Cruiser and.kept the Jeep but I will fix this!

 

[rasband]

Make sure you grease all the zerks up front too, I had some play due to those being pretty dry.

 

[Yendra Built]

I do still have 100 series to haul the grand kids though.

Ok so here it is, the frame of 2005 wrangler.

Notice how the track bar hangs far enough below the frame to act as a lever, and that the steering gear is forward from there. Then we have the relatively small tube cross member all the way out front.

Here is a picture of the front of my 1977 early Bronco. Large cross member just below the front of the engine with the track bar just behind it. The cross member also has an angle brace to the location of the motor mount. Steering gear in front of cross member and track bar mount behind.

Early broncos and F150’s of that era had crap track bar bushings on the axle that after time would cause wheel shimmy. But death wobble is different. On the Jeep frame notice the body mount location in a place to shake the hell out things...

 

[pagrey]

Ok so I sold the Land Cruiser and.kept the Jeep but I will fix this!

After you fix yours and maybe a few others we'll start taking notes. Until then maybe just read what others with experience fixing the problem say.

 

[AndyG]

A Jeep is a light , light , 1/4 ton vehicle, slap mud tires on it big enough for a one ton truck , drive it 10-15 years, wheel the crap out of it, and then be very upset when it starts going nuts .

I’m not bashing anyone , but the real root cause of most (not all, Mr. Blaine had a low tire cause it) death wobble is somewhere in that mindset .

I run 33” tires , so I’m not innocent either . I also had a mullet years ago. Anything to be cool , anything..

My point is Jeeps aren’t defective , people are .

 

[Yendra Built]

My particular Jeep was a very lightweight Jeep with a 2.4 engine and automatic. I felt that it was more susceptible to death wobble because of this. I did all of the normal fixes, balanced tires, alignments, track bar, ball joints, etc... Now I am installing a 4.0 and a 6 speed, so it may be better because of that. In the process of this con version I will build a cross member under the engine and at the track bar.