Hydraulic Brush Cutter Gearbox RC-51H 251390 Replacement Gearbox with 11.93 Speed Up Gear Ratio 59740978OE Number 251390 Features RC 51H This gearbox features a Hydraulic Motor Mount with a 1: 1. 93 Speed Up gear ratio and a internal 1 1 4" 14 Spline for hydraulic motor, with a 2" 15 tapered spline output shaft for use on many Skid Steer rotary cutters. Each gearbox features high speed bearing units and heat treated gears and shafts to ensure long life. Has a Four bolt mounting matches industry standards, 4 3 4" on centers. Each gearbox includes blade