Which of the following describes the Telma Transmission Retarder’s operating stages?

The Telma Transmission Retarder is designed to provide additional braking force to a vehicle's braking system, effectively enhancing safety and control during operation. Its design incorporates multiple operational stages to adapt to different driving conditions, and the correct choice emphasizes that the first stage operates when the vehicle is off throttle.

When a driver decelerates and takes their foot off the accelerator pedal, the Telma Retarder engages its first stage. This stage is pivotal because it allows for braking without engaging the traditional brake system, which can help reduce wear and heat buildup on the standard brakes while providing smooth deceleration.

Other options do not accurately reflect the operational characteristics of the Telma Transmission Retarder. For example, stating that all stages are automatic implies a level of operation that doesn't account for the driver's influence on engagement, whereas the presence of various stages acknowledges that the retarder can function at different levels of activation depending on the vehicle's speed and throttle input. Hence, the emphasis on the first stage's operation when off throttle highlights a key aspect of how the Telma Retarder is designed to function effectively in real-world driving scenarios.