Gear-down protection delivers up to a 2% fuel economy improvement by encouraging drivers to stay in the top gear. This is one of the more promising engine parameters for improving fuel economy while not affecting the overall performance of the freight-hauling operation.
Gear-down protection delays gear down when climbing a hill, causing the truck to go at a lower speed but use less fuel. When the vehicle is in a gear other than top gear, the maximum road speed will be set lower than the allowed top speed. This encourages the driver to operate in top gear, allowing the engine to run at its most efficient operating range. The engine also can detect the vehicle load and will allow higher road speeds with heavy loads in lower gears to prevent vehicles from slowing down too fast in top gear. For gear-down protection to work properly, transmission setup and vehicle speed sensor features must be tuned correctly.