did you get a new track bar or drill a new hole for it?
it could be many things man,
- loose track bar
- unbalanced wheels and tires
- loose lower or upper arms
- loose tie rod ends
- bad bushings in the upper arms
- steering angle(may need a drop pitman arm)
like these guys said, get under there, make sure your lower arms are torqued down to about 120 on both ends. make sure your track bar is torqued to about 35 or 40 pounds. also, i just put this lift on about 2 weeks ago, when i first put in on i had all kinds of vibrations, i simply went under and tightened everything, lower arms, upper arms, tie rod ends, steering box, track bar, and there was no more vibrations. hope this helps you out man, good luck and let me know how you like your kit!
-Nate.