1991 Ford F Series Trucks Ring and Pinion Set F-350 - RWD - Dana 80 Rear - Thin Ring and Pinion Set - 3.73 Ratio - Fits 4 Series 4.10 & Up Carrier - Rear guaranteed to replace your current 1991 Ford F Series Trucks Ring and Pinion Set F-350 - RWD - Dana 80 Rear - Thin Ring and Pinion Set - 3.73 Ratio - Fits 4 Series 4.10 & Up Carrier - Rear. 1991 Ford F Series Trucks Ring and Pinion Set comes new OEM 1991 Ford F Series Trucks Ring and Pinion Set aftermarket new 1991 Ford F Series Trucks Ring and Pinion Set of remanufactured 1991 Ford F Series Trucks Ring and Pinion Set F-350 - RWD - Dana 80 Rear - Thin Ring and Pinion Set - 3.73 Ratio - Fits 4 Series 4.10 & Up Carrier - Rear.