Edgar, can you provide a step by step on how the do that with
hpt beta 2.25

 

It's your transmission settings. It's related to TCC Lockup.

My wife's Acadia did the same thing. I was able to get it to stop. Once the TCC locks, it doesn't fluctuate anymore.

 

I know that, but I looked and didn't see the route to follow, that's why I asked, I am a hobbyist tuner not a pro.

Edit, I looked again, that function was done under TCC Duty Cycle for 6 speeds.
The 8 speeds are tuned with beta 2.25 or the new 3.0 and that function doesn't seem to exist in the menus.
I could be incorrect or missed it.

 

Any data behind your statement?

 

Do you have any facts to back your comments up? Hopefully you own a A8

 

mine is a 6 speed... with Circle D stall...

 

FYI,

there is a recent tsb on this issue, quoted in this link.
This is exactly what my truck is doing.
Shake Shudder on Acceleration and Cruise PIP5337 8L90 8 Speed - Page 4 - 2014 / 2015 / 2016 Silverado & Sierra Issues, Troubleshooting, & Recalls/Service Bulletins - GM-Trucks.com

To summarize, some dealers are changing torque convertors, some are doing a reflash, there is some debate on whether the new torque convertor is the same as the old one.

 

Thanks for the update. What is a "pip" or "pi"?

 

Not sure, some kind of internal Gm bulletin.
Must be similar to a TSB.

 

I forgot I know a tech. Preliminary repair procedure, as it is spelled out in the report...double flush tranny, if that doesn't fix it, THEN replace TC. Flushing the transmission seems like a band aid fix to me.