3 weeks ago heard dull knocking sound in front end. Had all bushings replaced and inner tie rod ($800.). Still heard noise. Had front struts replaced ($826.). Still heard same noise. Dull knocking in left front near firewall at low speeds. Repair shop replaced all bushings at no charge. Sound is still there. Repair shop now says that complete steering rack needs replacement because sound is from area where tie rod connects to rack on driver’s side. Other side is ok, and there are no leaks. Is this actually needed? And if so, what should it cost?