Yesterday, it was -7 degrees F when I left my house for work. As I drove to work, I noticed that I had no overdrive.

Even thought the truck (coolant) warmed up to operating temp after a few miles, my transmission never reached temps over 100 F (which is as low as my trans temp gauge goes, the needle never moved). It is likely the transmission never reached temps over 50 F degrees because the PCM prevents engagement of the converter clutch and overdrive clutch when fluid temperature is below 50 F. When I left work, it was warmer outside (about 10F), and my trans got up to about 120F, and overdrive worked fine.

So this morning, temps were about the same, but I put in my cold weather grill inserts this morning before I left for work. Not only did the coolant warm up much faster (which is nice for the in cab temps), my trans was up to around 110-120 in not much driving time at all. OD worked just fine this morning.

So, if you find that on very cold days, you are having problems with your overdrive and you have an auxillary transmission cooler, it is a good idea to cover it with cardboard or prevent air from coming in the grill on it somehow.

 

Great tip. My Tranny collor line from my Aux cooler blew off yesterday. I went from all power to none in about 30sec's. Took 7 quarts to be able to move again and had fluid all over the place under the hood and underbody,. Washed it all off and the truck sat in the heated shop all day.

Its rigged for now with a simple hose clamp, new end fitting should be here today from stealership.

 

I had that happen once, coming home at 3am and -40ºC weather. I was about 1-2km from my house, that was a crappy walk! I made double sure that those lines were clamped on good now...

 

Could the cold weather be why i started the truck the other day and the O/D Off light was on?. It resets when shutting the truck off, and this time when i started it, the light was on

 

Geez...I am glad I will never see -7 Deg here in the Nashville area (never say never, right?). Good tip...

 

Mine didn't exhibit that, but it could be possible. What was the ambient air temp?

 

I have a piece or card board over about 60% of the radiator... about 4 inches showing on each side and about 2in top and bottom.. just remember to take it off on those mild winter days! last year we had 67 degrees one day.. and 3" of snow the next! that's Ohio for ya!

 

hahaa -7? thats crazy, yesterday when i woke up it 16 i tohught that was cold and it didnt get above 34. tomorrow the high is about 68 or 70 i believe. Man i Love Texas!!

 

Hahaha, that makes me laugh.

Over the weekend it was -31ºC/-24ºF here BEFORE the windchill. Add windchill and it was -43ºC/-45ºF.

 

I know what you guys are talkin about, must have only been about 68 degrees this mornin..........brrrrrrrrrrrrrrrrrrrr