Transmisson warm up

Are these transmissions programmed to shift differently in cold weather? Bought the truck in summer and now seems to be a noticeable difference in the way it drives especially on colder mornings. Slower harsher shifts, etc.

Not really an issue, just curious to learn.

 

They all are programmed to shift differently. TCM has a learning map that controls solenoid modulation based on ATF temperature, so the system operates with the designated line pressure and allows enough time for plungers, etc to switch states. I.e. in cold weather the transmission may feel less robust - that's because it takes more time to fill up or drain accumulators. Also the upshifts are moved further up in RPM range, to heat ATF up quicker.

 

Does it eventually warm up and shift normally?
My 21 requires the pan temperature to reach ~ 100°F before one of two things happen. Either it holds 5th gear or the torque converter remains unlocked. My Scangauge monitors transmission temps. I leave our RV park, swing by the dumpster then pull out on a 55 MPH two lane. I noticed it takes about a mile of driving before the RPM settles down to the normal cruise RPM.

 

@Retired...finally yes it does. seems to take a bit but it does. My commute in the mornings is basically one stop light and then I am on the interstate for 20 minutes. I think the cruising and lack of shifting means it takes longer for the trans to heat up because there's not much load or gear changing.

RPM seems to settle but shifts are still slower

 

@vtl sweet! thanks for that detailed response. Ive got a 2023 and this is my first 10 spd, I'm used to a 6 speed so its taking time to get used to how this thing shifts lol

 

My 6 speed in my 2019 and my 4 speed in my 2000 do the same thing. Cold ATF fluid doesn’t care what transmission it’s in.

 

Normal and 100% better than my last truck I owned. It would make you nauseous.

 

@pwpblue So you have also noticed some weird shifts with your truck when cold? My issue is mostly highway related on cold mornings. I can get a pretty aggressive downshift on a pass. But once its up to full temp it seems to go away. I live about a 10th of a mile from the interstate so my trans does not get much warm up before then and its been in the teens and 20's here is TN

 

Just a delayed downshift and you can just feel it coming to a stop. Very minor as far as I'm concerned. I owned a f150 with 10 speed and was sickening when cold so Toyota is alot better.

 

It can shift up and down perfectly in almost any temperature range. Well, besides when it's too cold, like way-way below 0, and ATF is like honey, or when way it's too hot, like 300, and valve body looses too much linear pressure.

TCM has solenoids adaptation tables, which the software looks at and interpolate between temp points for the best gear shift. The problem is a regular adaptation is happening very slow, over a course of hundred miles, thus a regular day to day driving does not provide enough input while ATF is cold. This is why it shifts best when ATF is in operational range, because it spends most of time there and simply has more input for adaptation for that temperature range.

But if the first thing you do in the morning is connecting TIS and putting the transmission in forced adaptation mode then within a few mornings it will learn how to shift better in cold. I do it in my Volvo, which has Aisin transmission and TCM software (they all operate using same principles for decades), and shifts perfectly in any temperature. I've even added a button to my DIY touch screen drop it into adaptation, can do it without attaching a dealer-grade scanner.

 

So now everybody is going to want one!
Lol

 

It's opensource. This is how software engineers spread their seed.

https://github.com/vtl/volvo-ddd

 

I wish Ratio tek made a shift kit for our trannies. I’m sure later on they will, I have one of their shift kits installed in my A10 Ford tranny. Shifts like a dream, weather I’m driving normally or in sport mode. Awesome kits!