Here are some reasons why the overdrive off light might come on:
- The driver has manually turned off the overdrive gear. This can be done by pressing the "Overdrive Off" button on the gearshift lever.
- The transmission is in limp mode. Limp mode is a fail-safe mode that the transmission enters if it detects a problem. In limp mode, the transmission will only operate in the first three gears, and the overdrive gear will be disabled.
- The torque converter is slipping. The torque converter is a fluid coupling that connects the engine to the transmission. If the torque converter is slipping, it can cause the transmission to overheat and go into limp mode, which will disable the overdrive gear.
- The transmission fluid is low. Low transmission fluid can cause the transmission to overheat and go into limp mode, which will disable the overdrive gear.
- The transmission filter is clogged. A clogged transmission filter can restrict the flow of transmission fluid, which can cause the transmission to overheat and go into limp mode, which will disable the overdrive gear.
- The transmission is faulty. If the transmission is faulty, it may not be able to engage the overdrive gear, and the overdrive off light will come on.
If the overdrive off light comes on, it is important to take your Expedition to a qualified mechanic for diagnosis and repair.
