I just installed my first lift kit yesterday, and now if I hit a bump at 10-50 mph the front end shakes so violently I have to pull off the road and come to a full stop. Any ideas on what I could do? It was the 4" rancho sport suspension with rs9000xl shocks on a 2008 JKU, thanks for all the help.

 

Make sure everything is tight, especially your trackbar bolts

 

Sorry to hear you just joined the DW club. I chased this for almost 16 months. I have spent close to $4k and still not completely gone. The best advice I can give is to change out your front upper and lower ball joints, get the currie tie rod kit. Make sure you get the adjustable upper ball joints. And make sure you don't put back in the cheap ones from Jeep. You might also want to get a heavy duty adjustable track bar.
There are a couple of good writes up here. Do a search for Planman. He explained it the best.
Sorry and good luck.

 

Assuming your kit came with adjustable trackbars. Id so, simply torque your trackbar bolts to 125 lbs. The trackbar seems to be the culprit in most cases. If this solves it, go get some 9/16" grade 8 fine thread bolts and prevailing torque nuts and replace the 14mm OEM bolts.