Replacement 40 hp. gearbox 1:1.93 Speed up ratio gearbox with a 1-3/8" smooth input shaft with 1/2" shear bolt hole and circlip groove, 1.57" X 12 tapered spline output shaft and 1:1.93 speed up ratio. These are used on many of the Domestic and Imported Skid Steer Mowers currently being sold in the USA. Exact fit replacement gearbox includes the bottom castle nut and cotter pin . *****Please note this gearbox is shipped dry and will require 16 ounces of 90w120 or 90w150 weight gear oil or heavier!***** Replacement 40 hp. gearbox 1:1.93 Speed up ratio gearbox with a 1-3/8" smooth input shaft with 1/2" shear bolt hole and circlip groove, 1.57" X 12 tapered spline output shaft and 1:1.93 speed up ratio. These are used on many of the Domestic and Imported Skid Steer Mowers currently being sold in the USA. Exact fit replacement gearbox includes the bottom castle nut and cotter pin . Gearboxes are shipped dry and require 16 ounces of 90w120 or 90w150 gear lube added prior to using. If your gearbox has a 12 spline output shaft and a 1-3/8" smooth input shaft with a shear bolt hole and a snap ring groove this gearbox will work. Bolt pattern is 4-3/4" on center hole to hole and 6-3/4" center to center of bolt hole on diagonal. The mounting holes form a square bolt pattern. Replacement send my have a square, round or five sided housing, all specifications are the same! *****Please note this gearbox is shipped dry and will require 16 ounces of 90w120 or 90w150 weight gear oil or heavier!***** We sell many replacement parts for rotary cutters. If you don't see the parts you need listed please contact us we would love to earn your business. We are listing new items frequently so please check our store often. Part Numbers: 01-003 We stock a wide variety of replacement parts for Agricultural Equipment please contact us if you have any questions or if you would like more information.