[rconaway]

Gentlemen and Ladies,

I'm tearing my hair out on this one and could really use some help. My 2000 Ford Windstar with 165K miles and just passed emissions with flying colors (I run synthentic oil), won't stay in Overdrive. I get on the freeway 3 miles from my house. For the first 10-20 miles, the van runs fine. As the freeway mileage continues, anything above 75 mph makes the van drop down out of overdrive. As the mileage continues, so the does the speed that the van needs to maintain to stay in overdrive. Anything over 74, then 74, and so on down to 60mph and then eventually it just won't stay in Overdrive at all. If I'm driving an hour, it won't go back into overdrive at all, even under 40mph with no throttle.

The trigger to this is if I'm driving 75mph and I click the cruise control to go up 1mph, it should just slowly go faster. As the problem kicks in, it just downshifts and then may or may not go to overdrive. As I continue driving, it just won't go down.

I cleaned the MAF and the air filter. I did a complete tranny fluid change and also checked for codes. No luck. I'll take any other ideas before I pull the tranny.

[KBExperience]

is there an overdrive switch? i'd check that

[rconaway]

There is a switch on the tranny stalk on the console. It works normally when the tranny is working correctly. After the tranny starts staying in Overdrive, it won't do anything other than make the light go on and off.