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About blakearc

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  1. I agree, I would definitely prefer the issue to be fixed by GM. After searching this forum, this seems like a common problem with the 8 speed transmission. I love the truck but the hard shifting really bugs me.
  2. Hi Jerry, I recently purchased a pre owned 2017 GMC Sierra Denali with 30k miles. I am experiencing the same issues you are. For me its when I leave my house in the morning for work and pull up to my first stop sign in my neighborhood and get a very harsh down shift into 1st gear. It seems to be the worst when coming to stops at low speeds. The truck will lunge forward, its very annoying. I brought the truck to a local dealer who says they have identified the hard shift and applied a "relearn process". I was excited to think that this may fix the problem but it did not and my truck still has the same hard shifts/clunking. I am considering ordering a Range AFM disabler device as I've read that it improves shifting but I'm not 100% sure this will fix our problem (Maybe another member can chime in?) Do you have any updates or fixes for this problem yet?

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