Driver Technique

The ISX Gear Down Protection feature promotes increased fuel economy by encouraging the vehicle driver to operate as much as effectively possible in top gear, where fuel consumption is lower. It does so by limiting vehicle speed in the two gears immediately below top gear. Gear down Protection also senses engine load to ensure that the limit imposed does not have an adverse effect on performance. Using top gear lowers engine speeds and results in better fuel economy and durability.

Light and Heavy Load Effects on Gear Down Protection
There are two vehicle speed limits imposed by the Gear Down Protection feature: Gear down Protection Light Load Vehicle Speed and Gear Down Protection Heavy Load Vehicle Speed.

Under light loads, when the vehicle is operating 1 gear down from top gear, the vehicle will be able to travel no faster than the Light Load Vehicle Speed. If the vehicle is downshifted more than one gear, the maximum vehicle speed will still be limited to the Gear Down Protection Light Load Vehicle Speed . This gives the operator even more incentive to up shift.

When lugging uphill with heavy loads, Gear Down Protection allows access to the full operating range of the engine in all gears. Therefore, under heavy load, the operator can accelerate up to Heavy Load Vehicle Speed in the gear immediately below top gear. This allows the vehicle to perform well under heavy loads, but still encourages the use of the most efficient gear. If the vehicle is downshifted more than one gear, the maximum vehicle speed is limited to the Gear Down Protection Light Load Vehicle Speed.

Driving Tips
The ISX Gear Down Protection feature promotes increased fuel economy by encouraging the vehicle driver to operate as much as effectively possible in top gear, where fuel consumption is lower. It does so by limiting vehicle speed in one gear immediately below top gear. Gear down Protection also senses engine load to ensure that the limit imposed does not have an adverse effect on performance. Using top gear lowers engine speeds and results in better fuel economy and durability.

When driving under light load conditions, downshifting should be minimized. Attempting to run gear down in light load will limit vehicle speed. The extra engine speed will not result in higher vehicle speeds. Depending on how the feature is setup, it may even be detrimental to vehicle speeds.

Under heavy loads, extra vehicle speed will be provided when needed. Downshifting should be minimized as it will have a detrimental effect on vehicle speed. GDP will penalize ineffecient driving by limiting vehicle speed in a lower than required gear.

If the engine seems to perform poorly under conditions which REQUIRE downshifting, the Gear Down Protection parameters should be checked to ensure proper set up.