This technical repair manual covers the John Deere 4650 and 4850 tractors, produced in the mid-to-late 1980s. These heavy-duty agricultural machines are renowned for their robust engineering, reliability, and powerful John Deere diesel engines, offering substantial horsepower for demanding farm operations. Designed as workhorses for agricultural tasks, they represent a significant advancement in tractor technology for their era, prioritizing operator comfort and operational efficiency. The manual provides in-depth information essential for understanding and maintaining these durable tractors. This comprehensive manual serves as a definitive guide for owners, mechanics, and technicians. It details essential maintenance procedures, including fluid changes and filter replacements, alongside in-depth instructions for assembly, disassembly, and complete overhaul of major components such as the engine, transmission, and hydraulic systems. The manual also offers extensive troubleshooting and fault-finding guidance, supported by diagnostic procedures, component testing, and technical specifications including torque values and clearances. Its expert-level coverage ensures that users can effectively maintain and repair these John Deere tractors, minimizing downtime and maximizing performance.