In automatic transmissions, the device that replaces the clutch is the

• A. Hydraulic Pump
• B. Gearbox
• C. Planetary Gearset
• D. Torque Converter

Answer: (D)

In automatic transmissions, the device that replaces the clutch is the torque converter. It sits between the engine and the transmission’s gear train and uses transmission fluid to transfer power from the engine to the transmission without a mechanical clutch engagement. The impeller (driven by the engine) pushes fluid onto the turbine (driven by the transmission), creating torque transfer with the fluid providing a coupling effect. At low speeds, this setup also multiplies torque, helping the car start moving smoothly. Many torque converters include a lock-up clutch to create a direct connection at higher speeds for better efficiency.

The other options aren’t the clutch replacement: a hydraulic pump is part of the transmission’s hydraulic system but doesn’t replace the clutch by itself; the gearbox is the overall assembly that contains gears and mechanisms; the planetary gearset is the arrangement of gears inside the transmission. None of these alone replaces the clutch in an automatic.