A friend and I installed a lift on his discovery I. Was suppose to only be 2" lift. But he got sent the heavy duty springs instead of medium rate. After the install he has a bad vibration. Changed all u joints and still there. Shaft angles are pretty steep. Have done a lot of reading and have never read that driveshaft angles would play a problem with the 2" lift. But since he got heavy duty springs the lift is probably over 2". What can we do to fix the vibration. Any way of changing the pinion angle? I know double cardon shafts are probably a must now. Thanks for any info!