What type of automatic transmission uses a belt and pulleys?

The automatic transmission that uses a belt and pulleys is a continuously variable transmission (CVT).

Unlike a conventional automatic, a typical CVT does not select from a fixed set of gears. It uses two variable-diameter pulleys connected by a belt or chain. Moving the pulley halves changes the belt’s running diameter, continuously varying the ratio between the engine and drive wheels. One pulley connects to the engine; the other sends power onward.

“Belt” does not mean every CVT has the same construction. Steel-reinforced belts are common in lower-torque applications, while many automotive CVTs use a chain-like steel push belt. A CVT is also not the same as a torque-converter automatic: some CVTs may include a torque converter for launching, but their ratio-changing mechanism is different. The arrangement can keep the engine near an efficient or powerful operating speed, though real-world economy depends on calibration, vehicle weight, driving conditions, and efficiency losses.