1981 Ford F Series Trucks Differential Carrier F-250 - 4WD - Yukon Dura Grip positraction - Dana 60 - 30 spline - Full Float Axle - 4.10 and Down Ratio or Thick Gears - Rear guaranteed to replace your current 1981 Ford F Series Trucks Differential Carrier F-250 - 4WD - Yukon Dura Grip positraction - Dana 60 - 30 spline - Full Float Axle - 4.10 and Down Ratio or Thick Gears - Rear. 1981 Ford F Series Trucks Differential Carrier comes new OEM 1981 Ford F Series Trucks Differential Carrier aftermarket new 1981 Ford F Series Trucks Differential Carrier of remanufactured 1981 Ford F Series Trucks Differential Carrier F-250 - 4WD - Yukon Dura Grip positraction - Dana 60 - 30 spline - Full Float Axle - 4.10 and Down Ratio or Thick Gears - Rear.