Auto Transmissions

An automatic transmission is a type of gearbox in a vehicle that changes gears by itself—you don’t have to manually press a clutch pedal or select each gear like in a manual car.

Here’s how it works in simple terms:

• Purpose: It lets your engine run in its optimal speed range while your car speeds up or slows down.
• How it shifts: It uses hydraulic fluid pressure, sensors, and computer controls (or in older cars, purely mechanical systems) to decide when to change gears.
• Key parts:
  • Torque converter – replaces the manual clutch, connecting the engine to the transmission while allowing the car to stop without stalling.
  • Planetary gear sets – provide different gear ratios for speed and torque.
  • Hydraulic system / mechatronic unit – controls gear changes.
  • Transmission fluid – lubricates, cools, and provides hydraulic pressure.