This Service Repair Manual covers Komatsu WA65-5, WA70-5, and WA80-5 models with serial number prefixes H50051 and up. These machines are engineered for robust performance and reliability in demanding operational environments. While specific engine types, displacements, and power outputs vary by unit and serial number, the WA series is designed for efficient material handling and versatile application. The transmission systems, which can include Hydrostatic Transmission (HST) or Powershift Transmission (PST) depending on the model and configuration, provide precise control for various tasks. This manual provides comprehensive guidance for the maintenance and repair of your Komatsu equipment. It details essential procedures related to safety, general information, structure and function, testing and adjustment, and disassembly and assembly. Detailed specifications for engine, transmission, dimensions, and operational weight are available within. Furthermore, critical maintenance information, including lubrication capacities for engine oil and hydraulic systems, along with service intervals for engine oil and filters, are covered. This resource is intended to assist owners, mechanics, and technicians in ensuring the optimal performance and longevity of their WA series wheel loaders.