The steering gear box, probably.
If it's Power Steering, it may be coming from the pump itself.
This answer could be one of many things, if the grinding only happens while you are driving. Check to make sure your power steering fluid is full. Mine has a leak and every couple weeks it starts to grind when I turn right.
Check out the bearings in the steering column and the knuckles in the steering shaft
many reasons, steering pump, cv joints may be going out, or you could be grinding some plastic that goes around the wheel
most grinding noises that come from turning is usually a cv axle that needs to be replaced. Can also be a bad wheel bearing. If you hear the grinding when turning to the right then the left front wheel bearing is bad.
Classic sign of low steering fluid.
Inspect the steering components, suspension, and brakes.
Bad wheel bearings usually cause a grinding noise, and are known to only cause it when turning.
soounds like steering wheel fluid needs to up
bad rack and pinion
If its making a horrible grinding noise, it could be the bearing!
Power steering pump/fluid maybe
A few things could be causing a grinding sound when turning. It could be a cv axle, ball joint, tie rod end, or bracket pin steering.
The 2012 Ford Mustang's turning circle is 33.4 ft..