This manual covers the Komatsu WA270-3 and WA270PT-3 series wheel loaders, designed for robust performance in demanding work environments. These machines are engineered with powerful Komatsu S6D102E-1 diesel engines, delivering up to 140 gross horsepower, and feature the Komatsu Dynamic Transmission (KDT) with electronic control for efficient operation. With a typical operating weight of 11,630 kg and a bucket capacity ranging from 2.0 to 2.5 m³, these loaders are built for reliability and productivity in construction, material handling, and other heavy-duty applications. The purpose of this comprehensive English-language service manual is to provide detailed information for the maintenance, diagnosis, and repair of the WA270-3 and WA270PT-3 series. It includes in-depth coverage of structure and function, testing and adjusting procedures, and disassembly and assembly instructions. This manual is an essential resource for owners, technicians, and mechanics to ensure the optimal performance, longevity, and safe operation of their Komatsu equipment, covering serial numbers WA270H20051 and up for the WA270-3 and WA270H30051 and up for the WA270PT-3.