Which part of the braking system provides additional stopping power through the vehicle's transmission?

The transmission retarder is designed to provide additional stopping power by using the vehicle's transmission to slow down the vehicle without relying solely on the service brakes. This is particularly beneficial in reducing wear on the brake components during prolonged braking scenarios, such as descending steep grades.

By utilizing hydraulic resistance created through the transmission system, the retarder increases the vehicle's deceleration, allowing for smoother and more controlled stopping. It works in conjunction with the regular braking system and is most effective in heavy vehicles where excessive brake wear could be a concern. The efficiency of a transmission retarder makes it an invaluable tool for operators, especially in emergency situations or when navigating challenging terrains.

Service brakes and parking brakes fulfill different roles and do not utilize the transmission to enhance braking power in the same manner. Auxiliary brakes can refer to various other braking aids, such as engine brakes, but they do not specifically describe the function of a retarder tied to the vehicle's transmission.