In the name of God, and peace and blessings be upon the Messenger of God.. I have a 4-speed Caprice gearbox with an internal TransGo modification. I just bought the car and it has an electrical problem. I wanted to change the gearbox to a 6-speed with the complete wiring harness due to the wiring harness problem before. According to its owner, the gearbox is clean, and the sale is easy, God willing. Four speeds. You have the right to return it if a problem appears.