hello

I have a 2017 Denali XL with 65,000 miles. Just bought it used .

after driving it I've noticed that when slow acceleration from about 25 or 30 miles per hour the whole truck shutters.

the transmission almost feels like it's stuck in overdrive as it searches for the lower gear as you accelerate?

On hard acceleration it's not noticeable only on normal driving and it's really bad if you slowly accelerate...

My mechanic check the transmission fluid he said it looks good...

It's summery it feels like the transmission is slipping when you accelerate..

 

I could very well be wrong, but it might be your AFM kicking in and out. I have a 2017 Burb that does the same thing. I’ve read that it’s normal and no major issues with these 6-speed transmissions, but it sure is noticeable. I mitigate it by shifting into M and tap up to 5th gear while driving around town, but it still happens once in a while. Hopefully others chime in with their experiences and I’m always willing to learn.

 

The 6.2L uses the 8 speed.8L90. I found the Shudder Issue in a known issue. A transmission flush with the new Trans Flush machines at the Stealership will fix issue. Mobil 1 LV ATF HP fluid has to be used. Other trans fluid is hydroscopic. Over $500 for the flush! 22 quarts are used..

Here is GM link.. https://gm-techlink.com/?p=11127

Thanks for responding. Flush is schedule for late August... I'll post how it rides after...

 

Any idea if this would be covered under warranty? Or is it optional and chargeable? Sorry I’m not familiar with warranties. Mine has 4K miles on, purchased in Jan of ‘18..
*Just read the bulletin. ‘17 Burb is not listed..
on 8L45 and 8L90 8-speed automatic transmissions (RPOs M5N, M5T, M5U, M5X) in some 2015-2017 Escalade, Yukon; 2015-2018 Silverado, Sierra; 2015-2019 Corvette; 2016-2018 CT6; 2016-2019 ATS, CTS, Camaro; and 2017-2019 Colorado and Canyon models.