Pinion angle question.

So u measured the angles on the tail housing and on the pinion? Ur thinking back wards. U need the pinion at least 3* down from the tranny. If u leave ur tranny 3* down ur pinion would have to be 6* down. Then when u torque on it the pinion will move up to match the trans angle to cancel out any vibrations. Of our e there is cars with angles outta whack that don’t vibrate, which doesn’t make sense. Kim