What type of fluid goes in a 1986 f250 with a manual 4 speed?

For a 1986 Ford F-250 with a manual 4-speed transmission, you should use a high-quality gear oil, typically SAE 80W-90 or an equivalent. It's important to check the owner's manual for specific recommendations, as some models may require a different specification. Ensure the fluid is suitable for manual transmissions to ensure optimal performance and longevity.