[divotdug]

I just picked up a used 2017 SLT Acadia with 35k miles and found the 2-3 flare. Never noticed it in the test drive. Oddly enough in my commute there are two left turns on level ground where the flare is very evident and feels to be around 1/2s or so, enough to feel the vehicle to slow. I'd be interested if flashing solves or minimizes the issue.

I tend to believe the flare problem is not entirely transmission software related. In 3 years and 30k miles of owning an '18, I've never experienced a flare issue.

In my mind, I think it is a combination of things, driver style, transmission software and cylinder deactivation software.
Some owners complain about it, but does not seem to be a wide spread issue.

 

[Grantv]

I tend to believe the flare problem is not entirely transmission software related. In 3 years and 30k miles of owning an '18, I've never experienced a flare issue.

In my mind, I think it is a combination of things, driver style, transmission software and cylinder deactivation software...

Agree on driver's style and software. But can't see cylinder deactivation software playing any part. It never flares anywhere near where cylinder deactivation is possibly in play...

 

[speleos]

..
In my mind, I think it is a combination of things, driver style, transmission software ...

I'd think road grade and possibly transmission fluid temperature would have something to do with it, too.

 

[Grantv]

I'd think road grade and possibly transmission fluid temperature would have something to do with it, too.

Grade: Mine will only do it under light to medium throttle (so generally no downhill 2-3 shift), generally 2600-2900 RPM. So the grade is generally light. Steeper grade requires more gas/RPM's, and thus less likely to occur. But I can make it happen regardless, just forced lighter throttle/2700RPM shift point.
Temp: It is more so likely when the fluid is warmed up (a couple blocks is enough), but can be cold as well, just not as pronounced. Barely warm or higher temp tranny fluid makes no difference IME thus far.
P.S. I have mentioned before, the street that connects ours to the main roads to get to the highway have speed bumps. So I generally shift 1-2, then 2-3 is somewhat slowed due to the next bump coming. Does that play a part in my BCM learning my driving habits, and thus affecting my 2-3 shifts? I kinda think so.

 

[Grantv]

So I had my '19 in for its last free oil change today (first 4 free). Asked if they would flash the tranny programming again as the 2-3 flare still happens.
Instead of just doing so they tested it while up, and could repeat the flare.
Ordering a new valve body. From what I know though... the valve body might not fix it. I personally feel this is programming.
One thing I will say, it has never got worse over the almost 2 years, just has that flare...

 

[JayTee2019]

So I had my '19 in for its last free oil change today (first 4 free). Asked if they would flash the tranny programming again as the 2-3 flare still happens.
Instead of just doing so they tested it while up, and could repeat the flare.
Ordering a new valve body. From what I know though... the valve body might not fix it. I personally feel this is programming.
One thing I will say, it has never got worse over the almost 2 years, just has that flare...

Agree on the programming. I'm sure you'll let us know if it makes any difference. It may, initially, if for no other reason the transmission will have to go through "relearn".
But hope it does make a difference for you. . .

 

[Grantv]

Agree on the programming. I'm sure you'll let us know if it makes any difference. It may, initially, if for no other reason the transmission will have to go through "relearn".
But hope it does make a difference for you. . .

They flashed it, felt fine on the short drive home.
Will see more tomorrow. I am going to avoid the usual street out that has speed bumps, making me slow down right before the 2-3. Instead I'm gonna rip it up for a bit.
Not holding my breath on the valve body really changing it.
The tech guy said what I've been thinking... when warranty is up, get a tuner to make things more to my liking.

 

[cintocrunch]

Does anyone know how much it cost to have 18-NA-358 performed? My Chevy dealer won’t even schedule a transmission appointment they are so backed up and the GMC dealer wants to charge $135 to evaluate. If this repair is a transmission out repair I don’t see less than $1,000 and I’m not doing it at that point I’ll just ride it and see if it fails at some point.

 

[tekman78]

We've got a 2017 Limited. Got the vehicle form in-laws with about 27k on the clock. They drove this as softly as possible, and it's always been maintained.

The first time I drove it, I got on it pretty good off the line. Felt that flare between 2-3. I still feel it here and there, but it's really only when I'm pushing the throttle pretty hard, never during normal driving like I seem to see a lot of the complaints here. We're at about 34k right now. I did do a drain and fill at around 30k - don't really notice a difference.

From what I've seen here, it sure seems like doing any mechanical repairs (valve bodies) to this may be hit or miss. And I looked at 18-NA-358, which would seem to cover my model, but it seems many of the folks here complaining are the newer generation Acadia.

Would you mess with this if the 2-3 flare is only happening when you're busting out the lead foot? I'd be willing to go ask for a flash, but I'm sure getting to that point will cost me more time and money than I'm really looking to deal with right now.

Thanks,
Tim

 

[cintocrunch]

So I'm a couple months from 4 years with my '14 Traverse... Of course nothing showed up during the test drive and I really didn't start driving it until a couple months later when the Sonata needed some work, it was purchased a family hauler for me since my wife has a Pilot.

I bought it with 80k miles and I'm up to 125k miles now. It is a wonderful highway cruiser and does great on back roads with 40+ mph speed limits. I've changed transmission fluid at least 5 times via drain and fill.

Unfortunately, my commute involves mostly 30 mph roads and 8 roundabouts. Every single roundabout the Traverse comes in holding 3rd gear and if I baby it just right it will shift normally into 2nd, but most of the time it starts to rev up but without the corresponding forward motion (like it is caught in neutral or something) then slams into 2nd. The process takes maybe 1 second, it's very quick but there is a definite downshift "flare".

The upshift flare occurs more infrequently and honestly doesn't bother me as much. It's not a jolt that my wife or kids comment on and it only seems to happen if I'm in traffic and the trans temps increase but it's usually a one time thing since the temps come back down while moving.

I really like the way the Traverse drives and functions outside of this nasty shift flare issue and I'm hoping it's not overly expensive to fix or I will just deal with it.

 

[2ndGMC2011]

Wow.. I just read all 11 pages on this trans flare topic!!. I own a 2017 Acadia All-Terrain with 100K miles and have experienced the same flare issue(s) since new. I took it to the dealership early during warranty a couple times and they could never "replicate" the problem (stealer-ship was worthless on almost every warranty issue). After reading all the posts and considering my 5 years driving the Acadia, I pretty sure this is a software issue. More interestingly, like other software issues I have experienced, it is not completely repeatable! I used to think that the electrons driving software should be perfectly repeatable, but I have many examples to the contrary. For my particular Acadia trans flare problem, it can exhibit the flare very distinctly and then I turn the vehicle off, go into a store for 5 minutes, come back and start driving and it shifts just fine! After reading all of these posts I decided to post my own experience, which I rarely do, as I too am a lifelong GM car guy starting with a 70 Camaro. I currently own three GMC vehicles, the 2017 Acadia, a 2011 Acadia (spare) and 2016 Terrain (wifes). Ironically every GM car I drove exhibited at least one annoying issue that was unresolved over the entire time I owned it. I guess I'm just a sucker (plus I get GM discount since I worked for GM Allison Aircraft division for 12 years). My 1987 Buick LeSabre T-Type was my all-time favorite but my 2017 Acadia is a close second. I love the AWD traction and 310 hp! I am interested in aftermarket transmission reprogram if it ever becomes available. I really like this forum, keep up the good work!!

 

[AcadianAcadia]

They flashed it, felt fine on the short drive home.
Will see more tomorrow. I am going to avoid the usual street out that has speed bumps, making me slow down right before the 2-3. Instead I'm gonna rip it up for a bit.
Not holding my breath on the valve body really changing it.
The tech guy said what I've been thinking... when warranty is up, get a tuner to make things more to my liking.

I know this is an old thread, but I read through the entire thing and I’m very curious to know if the flash they did on your Acadia solved the issue. It seems some users have gone as far as replacing the entire transmission only to have the problem return. I’m experiencing the same stuttering issue as everyone else and I’d like to avoid costly repairs if possible.

 

[Grantv]

It did not solve the issue, only for a short period did it feel better after.
It always had the 2-3 shift oddity until the day I traded it in (Feb 12th this year). Never got better, never got worse either.
Add: I still think it's programming, not mechanical...

 

[JayTee2019]

Agree . . . If and owner's Acadia is out of factory warranty, but a tune and the 2 - 3 flare may be remedied.
Our 2019 had it also. The new 9 speed in out 2023 Acadia is much better. No anomalies I have noticed so far.

 

[divotdug]

I know this is an old thread, but I read through the entire thing and I’m very curious to know if the flash they did on your Acadia solved the issue. It seems some users have gone as far as replacing the entire transmission only to have the problem return. I’m experiencing the same stuttering issue as everyone else and I’d like to avoid costly repairs if possible.

Not everyone experiences the alleged stuttering issue. I had an '18 and now have a '23. I've never experienced any sort of stuttering.

 

[Grantv]

There was a guy on here who said he had re-programming figured out... only posted a few times.
I'd be chasing that down if I still had my '19.
But for sure yes, if I still had a unit that did the 2-3 thing, and out of warranty, I'd have it "tuned".
The 9 speed is so much nicer, ahhhh...

 

[AcadianAcadia]

There was a guy on here who said he had re-programming figured out... only posted a few times.
I'd be chasing that down if I still had my '19.
But for sure yes, if I still had a unit that did the 2-3 thing, and out of warranty, I'd have it "tuned".
The 9 speed is so much nicer, ahhhh...

I’ll see if I can find those reprogramming posts you mentioned …Mine is a 2018 Acadia and it is out of warranty. What exactly is meant by having it “tuned”?

 

[Grantv]

I’ll see if I can find those reprogramming posts you mentioned …Mine is a 2018 Acadia and it is out of warranty. What exactly is meant by having it “tuned”?

Same thing... tuning is reprogramming away from factory settings. People mostly do it for performance reasons, but also can be for tranny adjustments. Gotta find someone who knows what their doing of course.

 

[AcadianAcadia]

Same thing... tuning is reprogramming away from factory settings. People mostly do it for performance reasons, but also can be for tranny adjustments. Gotta find someone who knows what their doing of course.

Ahhh. Gotcha. Thanks for the clarification. Clearly, I’m a total newbie. I found one thread where a guy mentioned that he was able to fix the problem by tuning, but he also said it caused his gas mileage to decrease, which would be no bueno for me. Will a regular mechanic ever do reprogramming or is this more of a backyard garage kind of thing?

 

[Grantv]

Neither. Either a general performance shop or maybe a tranny shop that does mods.