ok so i had 4-4 drop the front springs have seemed to sag and i was getting sick of the rake. i bought belltech leaves and 3 in angled blocks and i still have the drive shaft vibration common with the extended cab s10s. i also installed airshocks if this has anything to do with it. im pretty sure its the pinion angle so what do i need to do to fix it? what degree shims do i need?