So on my recent move to California my jeep started to get really bad vibrations in 2nd and 3rd gear around 2000-2500 rpms It also started to make a very squeaky sound. Does this sound like a U joint issue.
I would start with balancing your tires. After that check the ujoints in the rear driveshaft. Also look at the shaft and see if there is any shinny spots. Possibly a driveshaft weight fell off? Also are your track bars adjustable?