When two members of a planetary gear set are locked together, what happens to the output shaft?

When two members of a planetary gear set are locked together, the output shaft will turn at the same speed as the input shaft. This occurs because locking the two components effectively couples them, allowing them to rotate as one unit. In a planetary gear set, if one part is held stationary (such as the sun gear or the carrier), and two components are locked together, they share the same rotational velocity.

This situation creates a direct connection between the input and output shafts, meaning that the output will mirror the input speed. Understanding this concept is crucial in automatic transmission systems, as it directly affects the way torque and speed are transferred through the drivetrain.