If I turn my steering wheel when the engine is on I feel a vibration in the steering wheel. little movement left and right and round corners it's fine because i'm not turning the wheel much. However If I do nearly a full lock I can feel it and hear it. I'm going to put new power steering fluid in my resevoir as it's an inch below the low marker then bleed the system, the noise isn't because it's low on fluid either as it's always happened. Sometimes when I look under my car, where the pipe comes from the reservoir and meets the power steering pump on one of the metal hoses I sometimes see a drop of hydralic fluid.