This Operation & Maintenance Manual provides comprehensive information for the Komatsu WA400-5 Wheel Loader, serial numbers 70001 and up. Engineered for demanding work environments, this machine embodies Komatsu's commitment to robust construction, operational efficiency, and long-term reliability. Its design prioritizes user productivity and ease of operation, making it a valuable asset across various industrial and construction applications. This manual serves as an essential guide for owners, operators, and maintenance personnel. It covers critical aspects including general operation, component explanations, transportation, cold weather considerations, and long-term storage. Detailed maintenance procedures, troubleshooting guidance, and information on attachments and options are also included. Safety precautions, essential for all operations and maintenance tasks, are thoroughly outlined to ensure safe and effective use of the Komatsu WA400-5 Wheel Loader.