The Oliver 60, 70, 80, and 90 Series tractors, produced from the late 1940s through the mid-1960s, represent a significant era in agricultural machinery. Known for their robust construction, reliable diesel engines, and versatile hydraulic systems, these tractors were built with Oliver's philosophy of durability and forward-thinking engineering. They offered functional efficiency and were designed to meet the demands of utility and agricultural work, solidifying Oliver's reputation for quality within the farming community. These models are recognized for their distinctive styling and engineering prowess, making them highly valued by owners and enthusiasts. This comprehensive workshop and service manual provides essential information for maintaining, diagnosing, and repairing the Oliver 60, 70, 80, and 90 Series tractors. It covers mechanical, electrical, and hydraulic systems in detail, including routine maintenance, scheduled service, and in-depth troubleshooting and repair procedures. The manual offers step-by-step instructions for component overhaul, engine and transmission rebuilds, and system diagnostics, alongside critical factory specifications and tolerances. This resource is invaluable for professional mechanics, experienced tractor owners, and restoration enthusiasts seeking to preserve the operational life and value of these classic machines.