Vibration / Rattle in Steeing Column

There is an obvious vibration ( No Noise ) that can be felt in the steering column when turning and hitting bumps. It is especially obvious on the highway while going around a turn you can feel a rattle right up through the steering wheel . I have brought the car to the dealership twice already and although they have confirmed the vibration they are unable to fix the problem .. They have installed Strut dampers ? and they admitted the 2nd time there is a clearance issue in the steering shaft that requires repacking ( which they did ) . Neither one of these repairs eliminated the problem. Any ideas ?

Thanks