First off I want to thank this forum fo all it's help.

I've recently changed my transmission fluid but haven't drained my torque converter. This was the first time sense '99 that I believe the filter and magnet have been changed/cleaned. After the all was changed/cleaned I took it for a test drive. All looked fine, the truck shifted better than the day i bought it (1999 5.4L 4X4 f-150 supercab, automatic), then I noticed once once shifting into Overdrive that the Overdrive Off light on my shifter started flashing. Whats going on?

This didn't happen untill after I changed the fluid so is there a sensor or something that i missed?

It doesn't happen all the time, it seems to only flash once the engine has warmed up while driving. Any suggestions?

thank you for the help!!!

 

You need to go get the codes read. Simple OBD2 scanners can't read Ford tranny codes, you need to go to a dealer, a tranny shop, or a shop that has an advanced scanner.

 

Technically, he needs a scanner the supports "manufacturer-specific" codes which are those between P1001 and P2000. About half of the potential transmission codes are in this category.

These are not particularly expensive, but the cheapest scanners, often those used at the auto parts stores, sometimes don't have this feature. Usually scanners from around $150-200 and up will do the basic job.