Definitely check your caster, but in my experience, it's almost impossible to get it dialed in right on the stock axle. Either your caster will be great and your vibration will be done, but your Jeep feels flighty. Or your steering feels great, but the vibration starts to come back.
That's one advantage (out of many) of upgrading axles. The brackets are moved to accommodate for the lift, so that you can set the ideal caster and not experience any negative steering feel.
I was just reading about a front driveshaft where you have a double CV joint on both the TC and the Diff. That seemed to help them a lot since they didn't want to upgrade the axle. I haven't seen anyone on here running one like that, but Tom Woods was the manufacturer.