If the fluid level is okay, it would be a good idea to flush the system.

To do this, place a drain pan underneath the pump area, disconnect the return hose and lower it into the pan to keep from making a mess. Plug the pump port from which you disconnected the return hose and pour in some fresh power steering fluid. Have someone start the engine and turn the wheel back and forth while you pour through two quarts of power steering fluid.

Remove the plug, reconnect the return hose and top off the reservoir. Start the engine and turn the wheel back and forth a couple of times. Top off the reservoir and replace the cap.

You are finished. You can buy power steering fluid at your local auto supply for about $2.50 per quart, making this about a $10 project.

Good luck,