GM/Chevy NV4500 4WD 1990-1995 Deluxe Rebuild Kit This kit includes a mainshaft, Complete Bearing and seal kit, 5th gear, updated 5th gear nut kit and all the spring and keys for the Chevy 4x4 NV4500 transmission. This will not work for a 2WD vehicle! If you need the 2wd mainshaft please as they are available but there are some differences to discuss. 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. This kit includes all new high quality bearings, seals, gaskets, high quality lined OEM synchro rings, an updated mainshaft, updated 5th gear nut, a new mainshaft 5th gear and the spring and keys. Note: We will need to know the tooth count of your mainshaft 5th gear it will either be 19 or 22 teeth Note: The 19 tooth 5th gear is no longer avaialble PLEASE NOTE: This transmission uses a 3 piece 1st and 2nd gear synchro rings. The outer rings and the inner rings are NOT included in this kit. This kit only includes the middle fiber lined 1st and 2nd gear rings because they are the only pieces that wear. We do stock the inner and outer synchro rings, so just let us know if you need them and we can add them to your order for just the cost of the rings if sent with your kit.