My vehicle- 1993 Dakota 4x4 automatic V6 with 178k miles.


Every single winter for the past 3 years my transmission turns evil. When it's very cold outside my transmission does not shift into 4th gear and stays in 3rd when I drive at high speeds like 55 or 65mph. When the truck gets really warmed up in the cold weather my tranny will shift into 4th gear but then downshifts into 3rd gear right away. Also I notice my RPMS show there is a problem because when I go 65mph the RPMs run at 3,000 and I know my RPMS should run between 1500 and 2100rpms at a high speed. So far I got a transmission fluid change and replaced my speed sensor on the transmission. Didn't make a difference.

I'm 100% sure that the cold dry air effects my transmission because in the spring, summer, and fall season my tranny runs like there is nothing wrong with it.

My questions......

1. How does cold dry air effect a transmission and could it be a electrical problem?

2. Torque converter solenoid?

3. What should I check and test on my truck?


Thanks

 

My guess is it is the coolant sensor.

 

really? How would a coolant sensor cause transmission problems? I did a coolant change like 3 weeks ago and I believe last year a mechanic replaced my coolant sensor.

After doing some internet research it might be transmission fluid problems. My transmission vibrates a lot more in the winter so maybe the tranny mechanic didn't do a good enough flush fluid change in 2008.

 

Yes it could be fluid problem.
The OD is controlled by the computer. If the engine is to cold the computer will not engage or may disengage the OD.

 

ok so i dont have any advice to help but i was curious what kind of vibration your getting as i think i may have the same problem. Thanks.

 

Like Crazy said, the computer won't shift the transmission into overdrive while the it is in its open loop (cold). Even if the gauge is reading right, the computer's ETC (the one with 2 wires) can be bad. I would definately start by replacing that.

 

Do you mean I should replace my whole computer?

 

No. Replace the ECT (engine coolant temp) sensor that has 2 wires on it. There are 2 ECT sensors on these trucks, the 2 wire one is for the computer, and the 1 wire one is for the gauge. Even if the gauge is reading normal, the computer's ECT sensor can be bad causing the computer to never go into closed loop where the OD can function properly.

 

I remember August of 2008 a mechanic replaced my coolant sensor because he said, the old one was broken or something and I didn't think much of it. I didn't mention this before, but I noticed that my cruise control doesn't work in the winter for some odd reason. It did the same thing last winter then worked when the temperature warmed up in the spring.

So does it mean anything if the cruise control doesn't engage when it's cold?