Not sure when overdrive is on or off
Overdrive acts like a final gear. It's easily noticed if it is on or off when cruising at higher speeds, as when operating the switch you will notice the engine revs alternate between higher and lower rev ranges.
When the engine revs drop, then overdrive is on, and when they rise, then it is effectively off.
The overdrive function works just like any other gear in that it reduces the torque from the engine to the wheels, and allows the engine speed to drop. This isn't always beneficial when climbing hills or towing however, or when driving hard, as you may prefer that the gearbox wasn't always changing gear into overdrive, as overdrive reduces the torque from the engine as a means to increase fuel economy and reduce stress. It is for this reason that the overdrive can be disengaged, effectively reducing the number of gears in the gearbox which you have available to you.
So simply put, for most drivers, in most circumstances, they will not need to turn the overdrive off.
In answer to the light on/off, the majority of vehicles have overdrive in the 'OFF' position when the light is on. It's a reminder light (amber) that you likely aren't employing the best fuel saving technique.
Nov 10, 2012 |
2002 Ford Expedition