1990 Ford F Series Trucks Differential Spool F-350 - 4WD - Dana 60 - Reverse Rotation - For Use w/35 Spline Axles - Steel - 4.10 Ratio And Down - Front guaranteed to replace your current 1990 Ford F Series Trucks Differential Spool F-350 - 4WD - Dana 60 - Reverse Rotation - For Use w/35 Spline Axles - Steel - 4.10 Ratio And Down - Front. 1990 Ford F Series Trucks Differential Spool comes new OEM 1990 Ford F Series Trucks Differential Spool aftermarket new 1990 Ford F Series Trucks Differential Spool of remanufactured 1990 Ford F Series Trucks Differential Spool F-350 - 4WD - Dana 60 - Reverse Rotation - For Use w/35 Spline Axles - Steel - 4.10 Ratio And Down - Front.