Which step is essential before attempting to start the truck after servicing an automated transmission?

Setting the park brake is a fundamental safety step that must be taken before starting a truck after servicing an automated transmission. Engaging the park brake ensures that the vehicle will not move unexpectedly, thereby preventing accidents or injury. This precaution is especially important in vehicles that may have components such as an automatic transmission, where unintended movement could occur if the truck is not properly secured.

In the context of truck servicing, especially after working on the transmission, mechanics need to ensure that the vehicle is stable and secured to safely conduct further assessments or operations. This step protects both the mechanic and anyone nearby from the risks associated with a vehicle rolling away.

The other steps, while important in their own right during the transmission service process, specifically pertain to the mechanical aspects of the transmission rather than immediate safety before starting the vehicle.