This is a GM/CHEVY and Dodge 4th gear on the countershaft for the multi piece cluster. This gear has 38 teeth and a 5.61 high ratio only. The gear is for the NV4500 in an early Chevrolet /GM and Dodge NV4500. You can identify this transmission in 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 1990-95 Chevy 3/4 ton or 1 ton gas and diesel trucks. You can identify this transmission in a Dodge by the cast "C-18157" or "C-23167". This transmission has an iron case with an aluminum top cover! This transmission usually comes in the 1994-ON Dodge Cummins Turbo diesel truck.