What is the best motor oil to put in a john deere 4440 tractor?

For a JOHN DEERe 4440 tractor, the recommended motor oil is typically a high-quality 15W-40 diesel engine oil, particularly one that meets the API CI-4 or higher specifications. It's important to choose oil that is suitable for agricultural use, as it provides better protection under various operating conditions. Always refer to the owner's manual for specific recommendations and any updates on oil specifications.