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So, today I took my 2017 Acadia Denali AWD to the dealer with this same complaint that I gave them last year on the shifting as mine too was doing the same harsh or delayed shift from gear 2 to 3. They tell me their tech reprogrammed the shift patterns and I can tell a difference even though that sounds like a good line for them to give me. ...
Did they give you a report, or "invoice" of any sort? Curious what they did. Would like to have mine improved when I take it in for my first oil change (probably in the next month).
 

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Been to my dealer 5x now.. and it’s still there again waiting on another TCM. Still no idea what’s wrong with it and apparently GM corporate is helping though I’m not seeing it.

Anyone else have a resolution to this shifting issue? I’m just waiting to get it back and off to buy a different car and trade it in. Can’t do this anymore.
 

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Either I am getting used to it or it is not doing it as much... Not sure which.
My wife says she hasn't noticed anymore either.

Still having the same issue. Its just an annoying issue and I worry about what will happen once the power train warranty runs out.
 

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Looking for any and all advice as I’ve been to the dealer 7x now with no resolution.

2017 GMC Acadia 6 speed 2WD Denali
35000k

Replaced already:
TCM
Transmission valve body
Reflashed trans software
Torque converter
Fluid flush numerous times through all this effort by the dealer
Spark plugs
Throttle body

Recent video footage of issue.:


Car only slips after trans warms up, ~10 mins after start from cold. Basically 2-3 shift feels like it drops into neutral for a split second before 3rd grabs. But.. only does this hot, never when trans is cold. I’m starting to think it’s a pressure issue or over/under fill? I need a trans expert to help me as I can’t stand it but otherwise love this vehicle. It’s ruining everything about it. Dealer is worthless at this point and refuses to replace whole transmission under warranty so far.

Any suggestions? Dealer claims output speed sensor is fine also last time they had the trans apart after checking the sensor upon my request.

Thank you!!
 

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Bump, anyone with similar symptoms or experience or resolution??
I've watched your video about a dozen times. While I have not seen this sort of flare in my '18 it also does not appear to be something that would particularly bother me.

Based on what has been replaced now need to look for the obscure. Some sort of comm error between various modules, or a crimped/damaged cooler line, or a wiring/connector issue.

Good luck.....
 

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I've watched your video about a dozen times. While I have not seen this sort of flare in my '18 it also does not appear to be something that would particularly bother me.

Based on what has been replaced now need to look for the obscure. Some sort of comm error between various modules, or a crimped/damaged cooler line, or a wiring/connector issue.

Good luck.....
I agree. I have tried to closely monitor shifts at time and seen maybe a bit of flare in the shift occasionally, but it doesn't seem to delay or affect vehicle movement. If it was every time or more pronounced I would be concerned.
 

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It happens every 2-3 shift after the transmission warms up.

It’s concerning and I’ll continue fighting with the dealer to fix it. Feels like the car suddenly stops moving forward for a split second. And although not the end of the world to everyone, it should not feel this way.

Thanks for the insights.
 

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Agree . . . the shift flare should not occur. It seems a lot of these newer 6, 8, 9 and 10 speed transmissions these days all have some quirks. They are a different breed and a lot of electronics in the controls involved along with the software.
 

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Just an anecdotal comment but I've noticed with mine that if I keep just a little bit of increased pressure on the gas pedal it will hold the lower gear much longer. I'm sure it has to do with the electronics thinking the engine is under load and delays the up shift.

Next time it happens see if taking a bit of pressure off the gas pedal has any effect.
 

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I am very familiar with this. I had it on my 16 Acadia and it has now started on my 19 Acadia with less than 4000 miles on it. Its in the programming. This car, and many others, defuel and/or reduce ignition timing during shifts. Someone here had at least one full trans replaced by his dealer and it still occurred. Amazing that a dealer was willing to replace an entire unit but to be sure, NO ONE wants to try and alter the factory parameters of either the trans TCM and likely also the ECM.

I am Soooooooooo disappointed in this car and happy Im in a 30 month lease but would still like to enjoy driving it. This thing shifts like a badly shifted manual quite a bit and sometimes falls on it face during the 2 to 3 shift. Freakin shame because I really like the rest of the car. But you know everything in my house shifts less than perfect- 2015 Mercedes GLK, 2016 Lincoln MKZ (an AWD pocket rocket in sport mode BTW). I am going to the dealer tomorrow actually and complain and see if there is some kind of update to the TCM or whatever.

Its really an annoying car to drive to be honest. It feels like it slips on the 2 to 3 shift. C'mon GM give us a break, these cars are alot of money to have many of us notice this flaw in programming. Honestly I WAS a dyed in the wool GM guy, NOT after this I'm not. really sickening TBH. After this lease I'm running to another brand unless I get any alleviation from Abeloff GMC in Stroudsburg .
'I'll let ya know.
 

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I've noticed my 2-3 shift is slow, but never realized it jumped up in RPM until today (darn quiet motor).
It probably goes up a couple hundred RPM, when it shifts strange, which is never under heavy throttle, not even every light throttle acceleration ...
Making an appointment. Hopefully they can fix this.
 

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Well 6/7 visits to the dealer, new TCM, torque converter, reflashes, new transmission body and fresh fluid galore... and now finally got a new transmission approved. Going in this week and fingers crossed it gets better or at least drivable.

Please raise awareness with your dealer if you have this 2-3 shift issue. It’s not normal and needs to be addressed. Tired of techs telling me it’s fine and then it starts doing it immediately on my drive home.

GM corporate was helpful but only to an extent. They really are just there to play the nice guy, feel good card. Comical really. But in the end they committed to replacing the trans so we shall see what happens. Dreading there is no change after all this...
 

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Mine is at the dealer as of this morning. I was able to get a video of it on the way there, showed the tech that first. He drove it (I ensured I was with him), and was able to repeat the RPM flash between 2-3 shift a couple times. He feels it might be the wave plate, or something else (can't recall). It is now with their transmission specialist.
After the test drive he checked the fluid; the level was right at the very bottom of the hatch marks, on the line, not in the hatch area. How is that even possible, it has 5700KM on it… (around 4000 miles).
So they are going to top it up/check it over.
Will post results.
 
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Well, top it up and reflash is all they did for now.
"Drive it until Monday, let us know if that fixed it. We are keeping the work order open..."
Will report back for anyone paying attention.
 

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Update; weekend held essentially the same issue. I now have an appointment for next Wednesday.
They indicated they will have to pull the tranny. Not even 6000KM (<4000 miles) on my new car yet. A bit depressing TBH.
 

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Jealous they are pulling your trans so quickly. Took me a million visits and all sorts of fixes before they got to that conclusion. And still don’t have it back......
 

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Wow, sorry to hear that. Before my first visit they indicated more may be done, all they did was top the fluid.
Will see what happens next week. One reason I have to wait they say, no loaner available right now.
 

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Wow, sorry to hear that. Before my first visit they indicated more may be done, all they did was top the fluid.
Will see what happens next week. One reason I have to wait they say, no loaner available right now.
Jumping through hoops to get something done is never enjoyable, nor is waiting.
We have only about 2,800 miles on our Acadia and haven't driven it much this winter. I have tried to take note of any 2 - 3 shift "flare" in RPM and perhaps occasionally there was a very brief upward sweep in the tach of maybe 100 to 200 RPM. . . and I really had to watch for it.

There was never any difference in driving feel or lag that we could feel. So will just drive and see after many more miles. Also, we have the extra 5 year 60,000 mile factory GM warranty we purchased at the time of the Acadia purchase. Glad to have done that for piece of mind that the factory warranty will continue for at least that long.
 

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Thanks JayTee2019.
This is the first new vehicle I've purchased since around mid 90's, a bit unhappy as one could imagine.
We bought my wife's 2014 Rogue used a few years back with around 20K on it. Now close to 60K, haven't had one repair; not a belt, battery, nothing.
 
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