This service manual provides comprehensive information for the DOOSAN DAEWOO DL420 WHEEL LOADER, covering serial numbers 5001 and up. Designed for demanding operational environments, the DL420 is engineered for robust performance and reliability. Its advanced features ensure efficient material handling and operator comfort, making it a valuable asset for construction, mining, and agricultural applications. The purpose of this manual is to assist owners, technicians, and mechanics in understanding, maintaining, and repairing the DOOSAN DAEWOO DL420 WHEEL LOADER. It details essential maintenance schedules, diagnostic procedures, and repair instructions to ensure the longevity and optimal performance of the equipment. By following the guidelines within this manual, users can effectively troubleshoot issues and perform necessary service operations.