This manual covers Komatsu SK714-5 and SK815-5 models, part of the 5 Series generation. These machines are engineered for reliability and performance, featuring hydrostatic transmissions designed for versatile operation. They are powered by the 68E-88E Series engine, a diesel unit with varying displacement and power outputs depending on the specific variant and application, built to meet emission standards of their production eras. These models are intended for demanding work environments where robust construction and efficient operation are paramount. The purpose of this comprehensive English-language manual is to provide essential information for the maintenance, operation, and repair of the specified Komatsu equipment. It includes detailed maintenance procedures, troubleshooting guides, and technical specifications relevant to the 68E-88E Series engines and hydrostatic transmissions. Safety instructions are also provided to ensure proper and secure operation. This resource is designed to assist owners, mechanics, and technicians in keeping the SK714-5 and SK815-5 models in optimal working condition.