Driveline Hitting underside of floor (at rear)

If the trans is 3* degrees tailshaft down then you want the pinion 3* nose up under power. This usually means the pinion needs to be from 1* degree nose up to 3* nose down at rest to compensate for wrap. With the Hotchkis springs its a crap shoot because of the amount of wrap is ridiculous. If you are to far nose down at the pinion you end up with vibration at cruise and decel.