How can I can cure my death wobble?

What is your definition of "death wobble".

Tell us exactly what it's doing.
Any time I hit a bump over 45 mph it starts to shimmy and I have to slow down almost to a stop. It had DW after I first liftes it two years ago, but I was running a stock track bar, so I out the adjustable on and it seemed to go away, until this past January it came back.
 
I had DW with the rusty's track bar as well.

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Any time I hit a bump over 45 mph it starts to shimmy and I have to slow down almost to a stop. It had DW after I first liftes it two years ago, but I was running a stock track bar, so I out the adjustable on and it seemed to go away, until this past January it came back.
Shimmy?
DW is pretty violent. I'm not sure I'd consider it a shimmy.
When real DW starts it will bring you right out of it.
Maybe that's what you have but I'd never call that a shimmy. It's rather violent.

Steering wheel going back and forth on it's own I'd call that a shimmy...but DW no.

Real DW is more like the front of the Jeep turned into a jack hammer.
 
Has anyone mentioned a dry steering test?

I saw a post earlier , on control arm bushings...Blaine pointed me to that once and it fixed a case I had ....seems he said the upper right front is one to watch.

So much can be at play, from a low tire to harmonics.... for my experience level I can track down a bad tire with a rotation usually and can track down loose components with a dry steering test ...and I feel like many cases fall in that category but certainly not all.

As to the posts describing it...it’s like a heart attack...you know when you are having one. There is nothing on earth that matters but bringing the vehicle to a controlled stop....and the word death is aptly used.

Its a Jeep’s way of seriously saying it needs attention up front.
 
Had the same problem on my son’s TJ. Installed a 4” lift and inherited death wobble that was initiated by bumps in the road at 45+. Through our process of elimination we replaced all steering ends, ball joints, unit bearings, track bar and control arms were new. New wheels and tires were road force balanced but still had death wobble. Not all the parts we replaced needed to be replaced but some did have excessive play. The front upper control arm bushings on the axle didn’t look bad but when we put a long punch through the bushing and moved it around the rubber bushing was very soft with a lot of movement. We replaced both bushings on the axle and no more death wobble. The cure seems to be different for each case but that ended up being our fix.
Mine do look/feel quite dead, I just ordered some so hopefully thats it.
To simplify things... DW is most commonly triggered by a tire problem. Imperfectly balanced or plain and simple a bad tire. I say 'imperfectly' because few tire shops take enough time to get them perfectly balanced as is required by the type of front-end the TJ and many trucks have. Most tire shops will only give their guys enough time to get the tires balanced to what they consider "good enough" which is seldom good enough. I had to get my tires balanced three times in one day by my local Discount Tire store. Their first two attempts had me on the verge of DW.

Based on you having a fairly recently installed JKS track bar installed with the bigger hardware on the driver's side (assuming both bolts are TIGHT), my bet is your DW is tire related.

And to be sure, true fully developed DW is beyond VIOLENT. It's so violent that drivers around you will notice and your vision will actually blur... you'll feel like a giant hand has picked up your Jeep with you inside and is shaking it like a pepper shaker. It won't stop until you come to a stop or at least nearly to a stop. If it's not all that it's not DW.
I just swapped my tires/rims today and still got death wobble. I am going to try replacing the axle side UCA bushings as they look and feel quite dead.
 
I hope the bushings are the fix for your DW like it was for us. Fortunately we have done all the work ourselves which saved us a lot of $ on labor costs and it’s been a great learning experience for my son to wrench on his Jeep. He has been driving the Jeep for about 2 months as a DD and still no DW. Installing a SYE and drive shaft this weekend.
 
I hope the bushings are the fix for your DW like it was for us. Fortunately we have done all the work ourselves which saved us a lot of $ on labor costs and it’s been a great learning experience for my son to wrench on his Jeep. He has been driving the Jeep for about 2 months as a DD and still no DW. Installing a SYE and drive shaft this weekend.
I hope so too I don't feel like dropping $900 on a steering box yet haha.
 
Just from what I have learned from all the great experience on this forum, the steering box is rarely the cause or fix for DW. Does your steering wheel have excessive movement compared to movement at the pitman arm?
 
If you've had DW as often as you're implying, some of your 'new' parts are probably trashed by now.