The EverTough transmission fluid from Eaton is a synthetic option for manual and automated manual transmission. Specially designed fleets with older truck populations and mixed-age vehicles, the fluid is good for manual transmissions across multiple makes an dmodels. Its typical drain interval ranges from 300,000 to 500,000 miles, and is designed for reliable performance without OE-grade specifications. EverTough also complements Eaton's PS-386 transmission fluid.