This Service Shop Repair Manual covers the Komatsu WA120L-3MC, a versatile wheel loader designed for various material handling applications. Built with Komatsu's renowned engineering quality, this machine exemplifies reliability and efficiency. The L-3MC Series represents a robust generation of loaders, equipped with features like articulated frame steering, heavy-duty full-floating axles, and a Powershift transmission, all contributing to its exceptional performance and durability in demanding work environments. This manual is specifically designed for models with serial numbers 54104 and up. This comprehensive 668-page English-language manual provides essential information for maintaining and repairing your Komatsu WA120L-3MC. It details critical procedures for preventative maintenance, troubleshooting, and testing, alongside in-depth technical specifications and diagrams. With detailed photos, drawings, and exploded views, this resource empowers owners, mechanics, and technicians to ensure the optimal performance and longevity of the equipment. The manual covers all major systems, including the engine, powertrain, hydraulics, electrical, cooling, and operator station, offering a complete guide for all service needs.