2019 equinox awd 1.5ltr 6 speed slipping

[americanchadazz]

my 19 equinox has 74,000 miles and the transmission slips when going into 3rd from 2nd and sometimes into 4th.

It only really does this when the outside temp is 70° and above and only does it when it goes through the gears the first time. I let the idle come down when first starting before I take off I sometimes sit in my car for 5 or so minutes when leaving work while its running before I take off. I dont just take off fast right when I put it in drive I have about a half mile drive at 15mph.

I take the highway daily and when I get off the highway the transmission slips worse shifts weird.

I have taken it to a very reputable or so I thought transmission shop 2 times the first time they couldn't recreate it which it was winter and very cold and only did it to me 2 times in a 3 month time period. So I had them do a drain and fill which they did 2 times, they drove it for a few miles and did it again.
The second time they found a code in the transmission and I guess the computer needed to be updated so they did that and said it was fixed. It slipped pulling out of their shop. I cant take it up there to really show them because it only does it the most noticeable on first shifting.

Does anyone have any idea what could be causing it? I am thinking its the tcm or whatever they call it for this car.

 

[PoManNox]

It's a little confusing to me because first you described the 2 to 3 shift slip happening only on the first take off. Then you mentioned it gets worse when you get off the highway.

My 2021 1.5 6AT seems to do a little 2-3 flair on a cold takeoff at times, but as you described, it's once and done and oddly, I've had other vehicles do the same exact thing with my conditions/driving style. I've just always attributed it to the powertrain being cold and the PCM/TCM doing it's thing to get everything up to temp.

At what mileage did you have the first ATF spill and fill done? There must have been no sign of metal in the drained fluid, or the shop would have wanted to sell you a new transmission, so I suppose that's a good thing.

I still get the weird front end wobble on take-off from time to time, even after having the TSB done (replace both front CV shafts) in 2024 w/ 34K miles on it. It's a lot better than what it was, but I ignore it now. Almost at 58K miles on my 2021 currently. I've done about 5 drain/fills on the trans starting at ~34K miles.

 

[americanchadazz]

Best i can describe it is when the transmission warms up it starts shifting weird and slipping more. But without fail every time when I first take off it slips going ito 3rd gear. Ive only driven trucks before I got this with 4L60's so I no idea. The shop that did the drain fill said the fluid was dirty but no metal. I got it done about 72,000 miles not long after I got the car.

I got the car jan 1st in michigan so it was below freezing that's kinda why im thinking its a computer going to crap cause it does it when it gets hot.

I wanna get a second opinion but the transmission shops around me are not the best. And I dont know alot about this transmission like I did with the 4L60

 

[PoManNox]

The 6T40 has been around for nearly 20yrs as far as I know. If it is not setting codes, not spitting metal into the pan and the vehicle is driveable, I don't think you're going to find anyone who's going to put any time into troubleshooting it until one of those things present itself, then they're just going to recommend replacement anyway.

These units have proven to be pretty darn reliable, even if their first fluid change wasn't till after 60K miles. Ideally you start drain/fills around 30K.

What you have going may not even be transmission related.

 

[americanchadazz]

How many miles should I be doing each change? Im not a machanic by any means but I do work on my own vehicles and family members vehicles and have a basic understanding. And with all this new tech on vehicles im getting more and more limited on what I know and can fix.

I do feel its transmission related because normal acceleration it will slip and the rpm will shoot 1,000, but again the newest vehicle I had before this was a 2009 sierra and before that was a 1999 tahoe.
So I cant go by feeling what the vehicle is doing to help me diagnose anymore.

Thanks for your replies and your time.

 

[PoManNox]

Ideally you do the first 2 drain/fills sometimes before 36k miles, then one or two every 30k. They're easier to do than an engine oil change on these. I mentioned "pan" above. There isn't a removable bottom pan on these, but they do have a 1/4" pipe thread drain plug. Lots of threads on the various forums on how to do the spill/fills.

I also use a votex brand magnetic drain plug on my Nox and traverse.

 

[Fouroaks]

If this is is t an actual slip but feels like a weird shift only on the first like 500 feet after starting I had an issue like this.

It turned out to be a faulty spark plug it took a dealer 5 attempts to locate it under warranty. I would start the car, drive slowly under 20mph to the first stop sign… run right into a road that was 55 and when accelerating it would shift, pause lurch forward slightly and then be fine,

It was a bad spark plug. I would check if the plug have ever been changed