Oh, great all with the same issue and no sure fix. I am having the same issue after re-gear. 05 lj 4speed auto OD. 4" lift, first and got slight vibs, installed SYE and adjusted angle and went down to almost nothing and tolerable. Then re-geared to 4:88 and much worse, pulled front DS and replaced u-joints and had balanced, only slightly better. I have not tried running it in 4 high at 65+ but I will try that next and see if there is any change. This is my first jeep and would really like to find a jeep pro to drive it and see if this is normal after