Choppy Stiff Steering

Has anyone else experienced choppy stiff steering? I have an 335 xdrive and recently my steering has gotten choppy. By choppy I mean it gets stiff when turning then instantly not stiff, then stiff again. It does not happen when the car is parked only when driving and occurs at high and low speeds. Checked the power steering and the fluid is clean and full. There is no moaning or clicking while turning. Checked my v-belt and the power steering pump pulley and both are in good condition. Checked for codes and there's nothing. Anyone got any ideas or had this issue before?



Thanks