* Transmission Fluid Issues: This is the most likely culprit. Low fluid level, dirty fluid, or incorrect fluid type can all cause the OD light to flash. Check your fluid level first – it's crucial. If it's low, you need to find out *why* it's low (leak) before just adding more. Dirty fluid likely means a transmission service (flush and filter change) is needed.
* Transmission Solenoid Problems: The transmission uses solenoids to control various functions. A faulty solenoid can prevent the overdrive from engaging properly. These are relatively inexpensive to replace but require some mechanical skill.
* Transmission Speed Sensor Issues: This sensor tells the transmission the speed of the vehicle. A faulty sensor can lead to incorrect shifting and the flashing OD light.
* Internal Transmission Problems: This is the worst-case scenario. Worn clutch packs, broken gears, or other internal damage can cause the OD light to flash. This often requires a costly rebuild or replacement of the transmission.
* Wiring Harness Problems: Damaged or faulty wiring in the transmission's electrical system can also cause issues. This is less common but needs to be considered if other components test out OK.
What to do:
1. Check the transmission fluid: This is the first and most important step. Check the level and condition of the fluid. If it's low, investigate for leaks. If it's dirty, a flush and filter change might help.
2. Have it professionally diagnosed: Unless you're experienced with automotive repair, it's best to take your Windstar to a qualified mechanic or transmission specialist. They have the tools and expertise to properly diagnose the problem. A simple code reader won't always give you the complete picture with transmission issues.
Ignoring a flashing OD light can lead to further damage to your transmission, resulting in more expensive repairs down the road. Get it checked promptly.
