This service and repair manual covers Case 4-390, 4T-390, and 4TA390 engines from the 390 Series. These diesel engines are known for their robust construction and reliability, suitable for a wide range of demanding applications. The 4-390 features a naturally aspirated configuration, while the 4T-390 and 4TA390 are turbocharged variants, all displacing 3.9 liters. With a focus on durable engineering, these engines are designed for consistent performance and longevity in various operational environments. This comprehensive English-language manual provides detailed information essential for the maintenance and repair of these Case engines. It includes in-depth repair procedures, technical specifications, and guidance on lubrication, filters, and cooling systems. Owners, mechanics, and technicians will find the necessary instructions for routine service, troubleshooting, and component replacement, ensuring optimal performance and extending the service life of the 390 Series engines.