1999 Dodge Durango Transmission

[73performance]

I know a person who purchased a 99 Durango. They were very happy with it, it's pulling power, the luxury, but the thing I'm asking about is that in this cold weather(it's averaging 20 below up here now for the last few weeks)the transmission won't shift to a lower gear when they are traveling down the interstate. It will go into the 3000-4000 RPM range before it shifts down. I told them that it is because it is in overdrive and dodges don't like cold weather alot, and that they'd have to put it into drive instead of overdrive. I told them it is nothing to worry about, just that you will be using more gas. Is this true what I told them? Or is there any way that this can be fixed or do they have to deal with this?

[John_Kunkel]

I'm confused, why would you want it to "shift to a lower gear when they are traveling down the interstate".  By a lower gear do you mean overdrive?

If so, there is a temperature sensor in the valve body that prevents OD and converter lockup if the fluid temperature is below a certain value. (around -5°F)