This manual covers the Komatsu WA420-3MC Wheel Loader, serial number A31001 and up. Engineered for demanding tasks, this machine embodies Komatsu's commitment to robust construction and operational efficiency. Its design prioritizes reliability and performance, making it a dependable asset for various industrial and construction applications. The WA420-3MC is built to handle a wide range of material handling operations, ensuring productivity and longevity through meticulous engineering. This comprehensive Service Repair Manual and Operation & Maintenance Manual provides essential information for the maintenance, assembly, disassembly, servicing, operation, and handling of the Komatsu WA420-3MC. It includes detailed procedures, troubleshooting guides, technical specifications, and safety precautions, all presented with clear illustrations and diagrams. The manual is designed to assist owners, operators, and technicians in achieving peak performance and ensuring the safe, economical, and effective operation and maintenance of the wheel loader.