Turning slowing and hearing a grinding noise could be your parking brakes. The parking brakes are attached to the rear hubs. They are like shoe and drums. The rear rotors are used as the drums. I would start there in my search.

The front noise while turning slow could be the steering column needing lubricating. I'm only quessing, because I have a noise while turning slow similar to tires turning while the car is standing still. The noise is coming from my steering column.

Hope this helps.