Martinova

No vibration when transmission is manually set to L9. It deactivates DFM, confirmed by many persons.

I have 2023 Sierra 1500, 5.3, 10 speed, low milage 10K, and noticed the same vibration at low speed. I thought I was a bit too picky but started to search and found very interesting posts. I also believe it's the transmission related to DFM. I had a Sierra 2021 and no such vibration problem at all! I was told by GM dealer in 2021, there was an association between GM and Toyota regarding 10-speed transmissions configuration so I guess that association was no longer effective in 2023. Pure extrapolation. I didn't search for that. The thing is; I found a video on youtube saying you can manually shift transmission speed to 1 lower speed, for example L9 if you have 10-speed transmission and it will deactivate DFM. I plan to try this out and see if the vibration will be there still. Keep you posted. I see GM is contacting people in this post. That's very appreciated. I would also like to be contacted by GM. Does anyone have any feedback about those private conversations with GM? Thanks!