Can levelling the track bar after a 4 inch front lift on my jk wrangler assist in sorting out continuing death wobble as have installed new track bar , ball joints, drag links and steering damper etc. with no effect and front and rear wheels are aligned to within 1/2 inch and tracking/ balancing is all in order?

 

Did you flip the drag link? What do you mean by "leveling the track bar?" Can you go into detail of what you replaced, and how recently? A picture of your front axle (from a few feet out, I want to see the steering and both tires in the picture) would help.

Did you check the holes on the track bar mounts when you replaced the bar? They shouldn't be ovaled out, although it's very common. Are your tires balanced? Are you sure it's death wobble, and not a shimmy? Do you need to come to a complete stop because it feels like the front axle is about to rip out of the Jeep if you hit any road imperfection?

Death wobble is terrifying, and you should stay off the roads until you figure out what's going on. Short list to check, at least for me, has been:
-Step 1: Remove steering stabilizer -- it'll only mask any issues
-Step 2: Ball joints (lift a tire off the ground, shovel under tire, check for play)
-Step 3: Front track bar (check bushings, mount hole for ovaling, and make sure it's torqued to 125 ft/lbs)
-Step 4: Control arms (check bushings, and make sure lowers are torqued to 125, uppers to 75)
-Step 5: Steering (check tie rod ends for play on tie rod and drag link)