[kan]

It would help to have a definition of "a bit too long" and to know the actual RPM's you are seeing.

George

"A bit too long", is something where you can feel the shift shouldn't have taken so long. Typically a second longer than what would "feel" normal to the driver.
It happens at different RPMs(I guess depends when computer decides to shift to 3rd gear)....typically in range 2K - 3K RPMs.

 

[speleos]

"A bit too long", is something where you can feel the shift shouldn't have taken so long. Typically a second longer than what would "feel" normal to the driver.
It happens at different RPMs(I guess depends when computer decides to shift to 3rd gear)....typically in range 2K - 3K RPMs.

Is this your first experience with the 6-speed automatic? My car behaves differently during weather changes and/or how long it's given an opportunity to 'warm up' before I drive. For example, it will sometimes shift to 3rd about halfway up the hill past my driveway. Other days, it won't shift to 3rd until I get over the top of the hill (at that point the engine rpms are higher). Been that way since new and through all the transmission reprogramming. That's just one example of the finicky nature of the beast. Everything you've discussed makes me wonder if you're experiencing something similar and trying to understand it.

 

[kan]

@jonwd @DenaliGuy
Do you guys still experience this? At 15K miles, there is no improvement for this issue. I am still experiencing this issue, as I did when I started this thread.
Did anyone else have new 2017 Acadia experiencing this?
Could this be a Torque Converter Clutch operation issue? If there some issue with TCC operation, can it be detected with OBD scanner?

 

[speleos]

... If there some issue with TCC operation, can it be detected with OBD scanner?

It would require a sophisticated tech tool to monitor TCC operation.

 

[jonwd]

@jonwd @DenaliGuy
Do you guys still experience this? At 15K miles, there is no improvement for this issue. I am still experiencing this issue, as I did when I started this thread.
Did anyone else have new 2017 Acadia experiencing this?
Could this be a Torque Converter Clutch operation issue? If there some issue with TCC operation, can it be detected with OBD scanner?

I'm still experiencing this but it's simply too occasional. I've had it in to the dealership twice but they can't produce the issue reliably. I even did a 30 minute ride-along with them; didn't happen once. I'm continuing to watch it and determine if I can determine conditions to reliably reproduce it. I'm curious to hear whether anyone else finds resolution to this problem.

 

[DenaliGuy]

I'm still experiencing this but it's simply too occasional. I've had it in to the dealership twice but they can't produce the issue reliably. I even did a 30 minute ride-along with them; didn't happen once. I'm continuing to watch it and determine if I can determine conditions to reliably reproduce it. I'm curious to hear whether anyone else finds resolution to this problem.

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.

 

[kan]

At 21K+ miles, I still have this issue. Taking it to dealer for oil change, will ask them to drive with me to verify the issue.
Found following threads which state same exact issue, shifts from 2-3. But these issues were with older 2013 and before models. So sad to find such issues from day1 on newer 2017 models.
Some of them had this issue fixed by reprogramming the PCM, for some it was waveplate issue, some posters didn't update about their final status.

http://www.acadiaforum.net/24-engine-drivetrain/14310-2013-acadia-revs-bit-high-before-shifting.html
http://www.acadiaforum.net/22-probl...qs-links/11526-transmission-problem-waveplate-slips-2nd-3rd-intermittently.html
http://www.acadiaforum.net/24-engin...ine-drivetrain/9624-vibration-jerk-before-shifting-2-3-acadia-2007-help-me.html

 

[jetfixer737]

Try this on for size...

I have the 2-3 flared shifts, but ONLY in low speed left turns! And they're big flares, the tachometer spikes up over 500 RPM during the shift.

I took my 2017 Acadia Denali in to the dealer for the 2-3 shift flare. After having it for the day and consulting with GM it was decided they would REMOVE & REBUILD my transmission (With only 12,000 miles on the clock) The trans tech replaced ALL the clutches, the pump and BOTH valve bodies. (Basically everything) After reinstalling the transmission he took it out to test drive and didn't even get off the lot before it flared again!
Another discussion with GM and it was decided to completely replace the transmission with a new unit, which was an adventure in itself since there were zero available anywhere in the country. Long story short, my Acadia (now with 16,000 miles) is technically on its third transmission. And you know what?

Its worse...

So as of now the dealer wants to wait a while to see if any software updates come out (Unlikely) then in the spring get an engineer from GM to come out and look at it.

 

[Jr85prix]

Try this on for size...

I have the 2-3 flared shifts, but ONLY in low speed left turns! And they're big flares, the tachometer spikes up over 500 RPM during the shift.

I took my 2017 Acadia Denali in to the dealer for the 2-3 shift flare. After having it for the day and consulting with GM it was decided they would REMOVE & REBUILD my transmission (With only 12,000 miles on the clock) The trans tech replaced ALL the clutches, the pump and BOTH valve bodies. (Basically everything) After reinstalling the transmission he took it out to test drive and didn't even get off the lot before it flared again!
Another discussion with GM and it was decided to completely replace the transmission with a new unit, which was an adventure in itself since there were zero available anywhere in the country. Long story short, my Acadia (now with 16,000 miles) is technically on its third transmission. And you know what?

Its worse...

So as of now the dealer wants to wait a while to see if any software updates come out (Unlikely) then in the spring get an engineer from GM to come out and look at it.

Just purchased a 2017 Denali and I have the exact issue. Any new updates?

 

[Basjer]

Try this on for size...

I have the 2-3 flared shifts, but ONLY in low speed left turns! And they're big flares, the tachometer spikes up over 500 RPM during the shift.

I took my 2017 Acadia Denali in to the dealer for the 2-3 shift flare. After having it for the day and consulting with GM it was decided they would REMOVE & REBUILD my transmission (With only 12,000 miles on the clock) The trans tech replaced ALL the clutches, the pump and BOTH valve bodies. (Basically everything) After reinstalling the transmission he took it out to test drive and didn't even get off the lot before it flared again!
Another discussion with GM and it was decided to completely replace the transmission with a new unit, which was an adventure in itself since there were zero available anywhere in the country. Long story short, my Acadia (now with 16,000 miles) is technically on its third transmission. And you know what?

Its worse...

So as of now the dealer wants to wait a while to see if any software updates come out (Unlikely) then in the spring get an engineer from GM to come out and look at it.

Same issue here. I have 34k on mine and the long shift between 2-3 has always been since day 1 on long left turns. Can reproduce roughly 90% of the time. Based on your experience, I may hold off even longer in hopes of a software update. Warranty almost up though.

 

[kan]

I am currently at approx 55K miles on my 2017 Denali AWD and the issue still remains and as most point its noticeable primarily on low speed left turns.
I have been observing the RPM meter closely for this 2-3 shift on left turns and one of the explanation "might be" that, this is due to gear ratios of this transmission.
What actually seems to happen is, the RPM's drop rapidly when this shift happens and since accelerator position hasn't changed (or since power output requirement hasn't changed), RPM's have to rise back again from the rapid drop. And my guess is this is what is giving this feel of flare or free-wheeling.

Typically during left turns the gear is in 2nd, RPMs at 3000. Then gear shifts to 3rd and RPM's rapidly drop to 1500 or so and then you feel loss of power and they come back again to 3000.
If Tranny was a typical ZF 8speed or more better spaced 6speed (like in CX5) then I think this issue wouldn't have happened.

Let me know what do you guys think about this suspicion.

6T75 M7X tranny used in 2017 Acadia : http://gmauthority.com/blog/gm/gm-transmissions/m7x/#tab-2

Gear Ratios
First:	4.484
Second	2.872
Third:	1.842
Fourth:	1.414
Fifth:	1.000
Sixth:	0.742
Reverse:	2.882
Final Drive Ratio:	3.160

Read more: http://gmauthority.com/blog/gm/gm-transmissions/m7x/#ixzz60sCu6RzS

 

[TriCoat18SLT1]

Has anyone performed the 30,000 mile trans flush service and noticed any difference?

 

[Markni12304]

Recently I have noticed that when driving my 2017 Acadia at slow speeds when shifting from 2-3 (need to double check if its from 1-2 or 2-3) it seems it holds RPM for a bit too long before shifting to the next gear.
This is probably more pronounced during slow speeds as vehicle is going smoothly and holding RPMs high is easily detectable at this speed.
Wanted to know if this is expected behaviour of 6T75 transmission or something is wrong?

If Denali displayed the current gear in DIC, it would have been more easy to know which shift. Plus for few its fun to know shift patterns. ;D

I just bought a 2019 Acadia Denali 3.6L (not sure if it has the 6T75-I will find out) but what you describe is exactly what's happening on a new 2019 bought in August with 23 miles.
I took it to the dealer and they said they worked with "corporate engineering". They rebuilt the transmission with all new seals and that didn't fix it. Then they put in a brand new transmission and that didn't fix the problem. I'm trying to figure out what to do now.

 

[Markni12304]

Has anyone performed the 30,000 mile trans flush service and noticed any difference?

At 1100 miles, I had a new 2019 Acadia Denali rebuilt with new seals and software reprogram. That didn't help. Dealer then put in a brand new transmission, that didn't help either. Same symptoms.

 

[hogdad]

Same driveline. Been there, Spoiled an otherwise nice car for me.

 

[steven.gregory.french]

Same issue here with 2017 Traverse AWD 34k on the clock approx.

Dealer says they can't reproduce. Here it is on youtube.

Any resolutions out there?

May need to ditch this automobile before the trans self destructs......

 

[steven.gregory.french]

Just came across this on the FLARE issue on 2-3 shift

If the car shifts from 2nd to 3rd with a slight delay/ rpm rise, or if you get on the gas and lift off when still in 3rd and the rpms stay and then drop, then back into 2nd (downshift). This is caused by the Output speed sensor, located behind the valve body, plugged into the solenoid pack. Cost from 40-50.

Transmission Rebuilder

First let me explain myself. I rebuild transmissions for a living. Ive ran into a several 6T70/6T75/6F50/6F55's in the past year. They are all mechanically the same. The Fords use a different Solenoid pack than GM. The cases are different, obviously. But the #1 problem with these trannys is...

www.taurusclub.com

 

[micahsd]

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.

I know most of you probably are thinking I'm crazy, but I can tell that it is shifting more rapidly through the gears compared to before. Overall, it seems better (not perfect as I had a few milder delays between 2-3 that were a lot less noticable)...time will tell as I just had this done today and drove it about 10 miles home (all was in-city driving). If something changes I'll post an update or rip this post down.

I did get a 2020 Acadia Denali as a loaner vehicle today during the work...the 9-speed transmission in that unit of course shifts a lot better.

 

[dsgvw]

Just had the valve body replaced, already done torque converter, TCM, and a reflash multiple times. Worse than ever now. I may raise the speed sensor idea with them but the dealer clearly has no idea how to fix this and won’t commit to a new transmission even with GM corporate involved.

I’m at a loss and it’s ruining my 2017 Denali. Might be time to move on.

How hard is it to replace the speed sensor? Might attack that myself for the price since the dealer will not just randomly replace that..

 

[speleos]

How hard is it to replace the speed sensor? Might attack that myself for the price since the dealer will not just randomly replace that..

Go to your 'net search engine, type in keywords "6t75 speed sensor" (use the quotes), and look at the part and diagrams which show up in the results. Then, decide if that's a job you'd like to tackle on your own. Good luck if you choose to do it.