This Service Repair Manual covers the Komatsu WA800-3E0 and WA900-3E0 3E0 Series wheel loaders, designed for heavy-duty industrial and construction applications. These machines are engineered for robust performance and reliability, featuring powerful diesel engines and efficient Powershift transmissions with 4 forward and 4 reverse gears. Their substantial operating weights and dimensions underscore their capability in demanding environments, making them essential equipment for large-scale material handling operations. This manual provides comprehensive guidance for the maintenance, repair, and servicing of your Komatsu wheel loader. It includes detailed information on specifications, structure and function, standard values, testing and adjustment procedures, troubleshooting common issues, and disassembly and assembly instructions. By following the procedures outlined within, owners, mechanics, and technicians can ensure optimal performance, longevity, and safe operation of the WA800-3E0 and WA900-3E0 models.