2018 GMC Acadia Denali 3.6 with 6T70 transmission - SHIFT FLARE

[bxd76]

I own a 2018 GMC Acadia Denali (AWD with tow package) and I occasionally get some slip, shifting from 2 to 3. I believe it?s called flare. It?s like a delayed shift where the RPMs jump a bit.

Curiously if I accelerate moderately to aggressively it doesn?t seem to flare. Only when driving gently around town.

I?m thinking of buying HP Tuners. I?m comfortable with cars and computers, I just haven?t tuned a transmission before.

I?m reading of other 6T70 & Acadia owners having success fixing this.

Is this TCC related?
What parameters would I be changing?

Thanks!
Brian

[bxd76]

After looking at HPTuners supported vehicle list, it looks like the second generation Acadia (2017-2023) is not supported at all. Not sure why, as I believe the transmission from the first gen didn’t physically change much but perhaps the TCM code changed.

[Russ K]

Did you try to read the PCM & TCM? As the supported vehicle list is not always up to date.

Russ Kemp

[HotRodNerd]

Late to the party, but I can confirm for the 2017.5 3.6L Acadia that you can read/write. IIRC it pulled up as a Colorado controller but it had full functionality and definitions.

I didn't completely fix the 2-3 flare, but approached it like GM 6L transmissions, shift times, TCC lock/unlock. I did dabble with Bluecat tool and input the data for the 6T70, it helped a bit but not a drastic improvement. That said, it was worth trying and ended up picking up another 1-2 MPG after tuning.