What should a driver be cautious about when using a retarder on slippery surfaces?

When using a retarder on slippery surfaces, the primary concern is that it can cause skidding. Retarders are designed to assist in slowing down a vehicle by using engine braking or a similar mechanism, which is helpful in many situations. However, on slippery surfaces like ice or wet roads, the sudden deceleration effect of a retarder can lead to a loss of traction. This can cause the wheels to lock up or lose grip, resulting in skidding, which can make it difficult for the driver to maintain control of the vehicle.

When the retarder engages, it increases the resistance on the drive wheels, which can exacerbate the slippery conditions. Therefore, drivers should be especially cautious using this feature in adverse weather conditions to avoid losing control of the vehicle.