shift into overdrive very slow

I have a 1998 Durango with a 5.2 engine and automatic transmission. The vehicle is parked outside. Sometimes when the temperature goes down around 20 degrees or colder, the shift into overdrive takes pretty long. The shift into second and third are normal, but the final shift into overdrive may take about 5 miles or so. After that the shifting is fine, and there is no problem in warmer weather. Question--is this the sign of a problem developing, and the cold temperature just making it worse, or can this be expected on very cold mornings ? The vehicle has 74,000 miles on it. I do plan on replacing the fluid and filter this spring.

20 degrees sounds a little high. The D's have a safety that will lock out overdrive @ -20. This will happen until the fluid is warm enough to flow freely through the tranny. My guess is bad thermostat down there, or maybe just some fluid gummed up around sensor.

Thanks cbreeze191 for the reply. Where is this sensor that you mention ? Will I see it when I remove the trans. pan, or is it internal to the trans ?

You mean you just jump in when it's freezing and take off? You don't warm it up at all?

BleedDodge, I only let it idle for about a minute before I take off.

Let it warm up then. It will never take overdrive if it's that cold out and you don't let it run for awhile before you drive it. Even still, that's real hard on everything to just fire it up and take off like that when it's cold...

Hey Mike, back again, I'm not totally sure where the sensor for at fluid temperature is. Quickly scanned the chilton's but didn't find much, although they do talk about several solenoids and electronic control mudules. Out here in the midwest when the actual temperature is -15 to -30 and the wind chill is around -50 you can let your vehicle run for as long as you want, but until you get in and start driving o.d. is going to stay locked out. Of course, it is good to let the vehicles "engine" get up to operating temp. Wind chill for those who don't know is what it feels like to the human body oh and metal objects out in the elements.

One other thing it could be is maybe a default code in the computer, don't know where you're from or if the D was originally from a warm climate area, but if that is the problem 15 mins in the shop will take care of it.

Well anyways good luck with the repair and trobleshooting. Keep us posted.