Did the lift come with a track bar relocation bracket that attaches to the front axle? My RC 4.5" lift did and I had terrible death wobble. I found that the bracket was just stamped steel and had no support to keep it from crushing when the bolt was tightened down. I put a spacer in and it was able to tighten up properly and it got rid of the death wobble.
My wobble was so bad people would back off behind me because they didn't know what the hell was going on with the Jeep. 45mph was fine, 46 was a no go.