This manual covers the International Harvester 454, 464, 484, 584, and 674 series tractors, also known as the Hydro 06 Series. Manufactured primarily from the early 1970s through the early 1980s, these tractors are recognized for their robust construction and workhorse capabilities. International Harvester, a historic American manufacturer, produced these reliable machines with a focus on mechanical durability. These tractors are equipped with direct injection diesel engines, typically producing between 45-75 horsepower, and feature a range of transmission options including fully synchronized gearboxes and hydrostatic transmissions. Their design emphasizes ease of maintenance and a long service life, making them a staple in agricultural operations. This comprehensive workshop service repair manual provides detailed information for owners, mechanics, and technicians. It covers all aspects of maintenance, diagnosis, and repair for the International Harvester 454-674 series tractors. Key areas include complete engine overhaul procedures for various diesel engine variants, detailed service for the fuel, cooling, ignition, electrical, transmission, driveline, steering, and brake systems. The manual also offers in-depth guidance on hydraulic systems, PTO operation, three-point hitch adjustments, and body/frame maintenance. With step-by-step instructions, clear illustrations, and extensive troubleshooting charts, this manual empowers users to perform routine maintenance, complex repairs, and system diagnostics efficiently, saving time and costs.