Pinion angle is checked against the driveshaft. The front u joint angle is the transmission output shaft checked against the driveshaft also. Both can be adjusted. Rear angle with leafs should be 5-7° nose down against the driveshaft. Will not make any difference with your clearance issue. That 5-7° is for drag racing. For cruising down to 2-3° is okay. Do not run 0°!
