This Factory Service Repair Manual covers the Case 4-390, 4T-390, and 4TA390 diesel engines. These 4-cylinder engines displace 3.9 liters (238 cubic inches) and are known for their robust construction and reliability in various applications. Engineered for demanding tasks, these engines feature a liquid-cooled system and forced lubrication for optimal performance and longevity. Their adaptable nature allows for integration with both manual and automatic transmissions, depending on the specific equipment. This comprehensive manual provides essential information for the maintenance and repair of your Case diesel engine. It details critical procedures, technical specifications, and troubleshooting guidance necessary for keeping your equipment operational. Coverage includes fluid specifications, recommended service intervals for oil and filters, and general maintenance practices. By following the instructions within this manual, owners, mechanics, and technicians can ensure the continued efficiency and proper functioning of the 4-390 series engines.