What type of power steering fluid for a 1990 F 250?

For a 1990 Ford F-250, you should use Power Steering fluid that meets the Ford specification, typically Mercon ATF (Automatic Transmission Fluid). It's important to check the owner's manual for any specific recommendations or requirements. Avoid using fluids not specified for Ford vehicles, as they may not perform adequately in the power steering system. Always ensure the fluid is at the appropriate level and in good condition to maintain optimal steering performance.