This manual covers the Komatsu WA320-3 and WA320-3 Custom Wheel Loaders, serial numbers 50001 and up. These machines are engineered for robust performance and reliability in demanding work environments. The WA320-3 is equipped with an S6D108 engine, while the WA320-3 Custom features a SA6D102E-1 engine, with detailed engine specifications available in separate shop manuals. These wheel loaders are designed for a wide range of applications, emphasizing effective, economical, and safe operation, alongside peak performance maintenance. This comprehensive English-language service and operation & maintenance manual provides essential information for the assembly, disassembly, servicing, and operation of your Komatsu wheel loader. It details structure and function, testing and adjusting procedures, maintenance standards, and troubleshooting guides. The manual also covers lubrication, safety precautions, operational guidelines, and the use of various components and optional equipment. It is designed to assist owners, mechanics, and technicians in maintaining the optimal condition and longevity of the WA320-3 and WA320-3 Custom models.