I have found out my driveline vibrations is being caused because my driveline is out of phase. One u-joint is 24 degrees and the other is 5 degrees at the differential. I could shim the spring pads but my caster is 4.5 degrees. I need to bring the front of the differential down to phase the driveline but it will throw the castor off. So what do you guys do? It is a S.P.O.A. with wrangler springs.