This is an input shaft for the GM / Chevy 5 speed NV4500 transmission. This input shaft has 20 teeth and is for a transmission with a 6.34 low ratio only. You can identify this transmission on a Chevy by the cast "C-16812" or "C-18157". This transmission has an iron case with an aluminum top cover! This transmission usually comes in the 1992-94 Chevy 3/4 ton or 1 ton gas and diesel trucks.