Rack and Steering column... Its the full part that connects your front two wheels and directs the movement to turn left or right... I started hearing poping sounds when i pulled into a real tight spot, thats the indicator it has worn down.. Not a serious need to fix today type of problem, but over time it could worsen and worst case scenario could completely fail leaving no steering control to the vechicle.. Repair cost at a dealership is about 2000$ which replaces the entire system and labor.