Moog sells "problem solver" upper and lower ball joints. Any one deal with them? When I hit 50 to 55 the front end goes into a very bad death wobble. Tie rod ends seem ok. Tires and rims seem ok.

 

My understanding of “death wobble” is this. Somewhere on the vehicle, one or more components is worn beyond tolerances, and when oscillation initiates from a suspension “traumatic” event (like hitting a bump or a pothole) or also when a vibration reaches a certain point and harmonic at a certain speed, it causes the other components to react. This is called the “multiplier effect”, where one component affects one or more other components as the event travels through the front end of the vehicle.

Death wobble is not uncommon with the XJ! It is even more common with a lifted XJ. Finding the worn component or components is not always easy and can sometimes be downright difficult. Sometimes it’s obvious, other times everything appears to be okay when you perform an inspection on a hoist, but getting the vehicle up in the air and going over everything with a fine tough comb is always a good first step. Have a friend turn the steering wheel back and forth full travel as you perform the inspection. It is very helpful if you know exactly how to perform a comprehensive inspection of every single front end part, looking for abnormal wear and or play in that hardware. If you do not know how to do this type of inspection, pay an experienced professional to do it. Be sure to ask them if they are familiar with “death wobble”, as not all technicians are versed in this…..

Check out the below link if you would like some extensive reading on “death wobble” causes and cures. From my research, Kevin (the author of this tutorial) is one of the best in the business with tracking down root cause of death wobble. He does offer hardware for sale that can help resolve death wobble, but even if you don’t buy any parts from him, you can still get some excellent ideas on what to look at in resolving your death wobble.

http://www.kevinsoffroad.com/how-to-...-death-wobble/

Possible causes of death wobble are listed below. Isolating death wobble is a process of elimination; the root cause is not always obvious and it can often be caused by a combination of things! Always chase and resolve death wobble because if it is not resolved, it is such a violent event that it has the potential to seriously damage front end parts. From my personal experience, I would first concentrate on the track bar and the control arms and associated bushings.
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-Front tires out of balance (try swapping fronts to rear; see if symptoms change)
-Tire pressure. Don’t laugh. It’s not a root cause but can exaggerate the problem. Experiment with lower tire pressure to see if it helps
-Improper lug nut torque on wheels
-Front alignment out of spec
-Loose track bar
-Worn track bar bushings
-Worn track bar (check for play!!)
-Bad control arms and associated bushings
-Worn/damaged steering stabilizer (not generally a cause in and by itself)
-Worn/damaged shocks
-Worn/damaged tie rod end
-Bad U Joint
-Bad ball joint
-Loose frame mount
-Steering box loose
-Bad front hub assembly

 

Short Version...
Don't throw money at it, it won't help.

Find the cause and fix it.

 

I had the death wobble, the first thing I did was check the track bar the hole on the web of the axle had been oblonged. I drilled it out and put a larger bolt in there with a new track bar. It made a change in how the front end felt but it did not cure it. The next thing I did was replace the track bar (junkyard and painted it), bushings and new links. I have not experienced the death wobble since but there are still some ride quality issues and there are many more things underneath that I intend to replace/upgrade. The track bar and sway bar helped but it is not 100%.

 

Start with rotating tires, balancing them, alignment and go from there. Those may be your cheapest solutions and if that doesn't cure it, move onto track bar, control arm bushings, tie rods, and the wheel bearings