What component adjusts the engine speed in relation to the rear wheels in a rear-wheel-drive system?

The component that adjusts the engine speed in relation to the rear wheels in a rear-wheel-drive system is the transmission. The transmission is responsible for transferring power from the engine to the drive wheels while allowing the vehicle to operate efficiently across various speeds and loads. It changes the gear ratios, enabling the engine to run at an optimal speed for different driving conditions, whether accelerating, cruising, or climbing hills.

By controlling the engine speed and torque output, the transmission helps maintain vehicle stability and performance. It ensures that when the rear wheels rotate, they do so at an appropriate speed corresponding to the engine's output, allowing for smooth acceleration and deceleration.

Other components, such as the axle, drive shaft, and gearbox, play important roles in the drivetrain but do not specifically adjust engine speed relative to the wheels. The axle transmits power to the wheels, the drive shaft connects the transmission to the rear axle, and the gearbox is another term for the transmission that describes the system of gears used to manage speed and torque. However, it is the transmission that takes on the critical task of adjusting and controlling engine speed appropriate to the vehicle's operation.