Front Suspension Shock Absorber problems of the 2003 Toyota Avalon

1) regular, normal driving on a daily basis, approximately 15 miles per day. ; 2) rattle of front, suspension area, especially noticable when driving over cracks, bumps, or pot holes on street, highway surface, 3) submitted vehicle to dealership for repair on three occasions, crown Toyota, ontario, CA. Technicians stated on first visit unable to detect any noise. Second visit, ability to detect noise apparent, but not enough to warrant repair. Third visit, ability to detect noise apparent, but not enough to warrant repair. When noise worsens, bring vehicle back into service. No parts were replaced or repaired to date.