This manual covers the Hitachi ZX225US-3 and ZX225USLC-3 excavators from the Zaxis-3 product line. These diesel-powered excavators are engineered for robust performance and reliability in demanding work environments. The ZX225US-3 and ZX225USLC-3 models feature advanced hydraulic transmission systems, including travel motors and transmission control valves, designed for efficient operation. With an approximate operating weight of 22,500 to 23,500 kg, these machines are built to handle substantial workloads, showcasing Hitachi's commitment to durable and powerful construction equipment. The purpose of this English-language Service Repair Workshop Manual is to provide comprehensive guidance for the maintenance and repair of your Hitachi excavator. It includes detailed, step-by-step instructions, clear diagrams, illustrations, and essential wiring schematics. Key areas covered include routine service for the engine, hydraulics, upperstructure, undercarriage, and front attachments, along with troubleshooting procedures for all major systems. The manual also contains important safety guidelines and disassembly/assembly precautions, ensuring that owners, mechanics, and technicians have the necessary information to keep the ZX225US-3 and ZX225USLC-3 operating at peak efficiency and safety.