A semi-automatic transmission is like a regular car transmission, but with a few differences that make it easier to drive. Unlike a regular transmission, the semi-automatic transmission doesn't have a clutch pedal. Instead of pushing the clutch pedal when you want to change gears, you push a button. Semi-automatic transmissions also usually let you choose between automatic and manual modes. The automatic mode will shift gears for you, just like a regular transmission, but in manual mode, you can manually change the gears with the shift lever or switch. All you have to do is push the shift lever up or down.