Chevy 4 Speed SM465 Rebuild kit 1968-ON 2nd Gear, 3rd Gear and 4th Gear Brass Synchro Rings for the GM SM465 4 Speed for years 1968-ON You can identify this transmission by the iron or aluminum top cover. It has 2 PTO Openings and has a 12" overall case length. 4 Speed transmission for years 1968 and on.