That's awesome! I took my Enclave to Buick telling them about the TSB. They were finally able to duplicate the problem after performing the power breaking procedure in the TSB. Now, I am waiting for my service advisor to get back to me. I am glad they were finally able to figure out the problem after about 18 months of me complaining about it and Buick telling me nothing was wrong with it. But, I am sure I am going to have to fight them on warranty since the car is now out of the powertrain warranty. Of course, it was under warranty 18 months ago when I started complaining about it. And this TSB was out in March, 2019 when I brought it in November, 2019. So, they should have been able to figure it out. Has anyone had experience with getting something like this covered since I have documentation of bringing the issue to their attention while it was still under warranty?My 2017 (31k miles) has been doing this for months. Once it shifts into 3rd, the RPMs will start to go up like normal (under normal acceleration) continuing to gain speed, then the RPMs will drop slightly and hesitate, then start to climb again. I would describe this as the trans trying to up shift again way too early, very odd. It does this under normal to light throttle.
I brought it into the dealer for a leaking radiator and power steering concern and to have them assess the shifting issue. They determined there is an issue and are replacing the upper and lower valve bodies as per the TSB.
Thank you for posting, very helpful!
Yup. It’s still doing it. The dealer has been very helpful though. But had to complain to GM because the problem still exist and the dealer told me I have to wait for 5k miles.Hi Vic. Did the dealer replace both the upper and lower valve bodies at the same time? My issue has been gone since the dealer replaced both of the valve bodies. Sorry some of you are still having trouble with this..