Another A8 shudder question
Thread Starter
2nd Gear
Joined: Jun 2021
Posts: 2
Likes: 0
Another A8 shudder question
We just purchased a 2015 Z51 with 19,000 miles on it. I was aware of the GM A8 transmission issue and tried to get the car to act up during the test drives, but didn't get anything abnormal. We bought the car and had a 180 mile drive home. During that time, the trans did start acting up and shuddering when starting to climb a hill on light acceleration. Felt like going over a rumble strip.
I have read through many threads on the issue here and it "seems" like the TSB (blue label triple flush) fixes about 95% of the cases.
My local dealer confirmed it has not been done, and will do the TSB for about $750 (GM will not cover anything).
I got the selling dealer to cover most of the cost, so that's not the big concern. But if it turns out to be more than that … like a converter or tranny.... that would be on me.
I have a 7 day, no questions asked return clause on it
I guess my question is, are my assumptions right about this curing the issue with 95% of the vehicles... or should I take this Vette back and run??
Appreciate any friendly advice from those that are in the know.
I have read through many threads on the issue here and it "seems" like the TSB (blue label triple flush) fixes about 95% of the cases.
My local dealer confirmed it has not been done, and will do the TSB for about $750 (GM will not cover anything).
I got the selling dealer to cover most of the cost, so that's not the big concern. But if it turns out to be more than that … like a converter or tranny.... that would be on me.
I have a 7 day, no questions asked return clause on it
I guess my question is, are my assumptions right about this curing the issue with 95% of the vehicles... or should I take this Vette back and run??
Appreciate any friendly advice from those that are in the know.
Burning Brakes
Joined: Nov 2016
Posts: 1,192
Likes: 437
From: San Dimas CA
Thread Starter
2nd Gear
Joined: Jun 2021
Posts: 2
Likes: 0
I was not watching the V4/V8 mode... when I noticed it most was when cruise was set and on a flat road (constant speed) and when the car would start to go up a slight hill, there would be a slight acceleration to keep speed and that’s when it happened.
I did notice the RPMs would fluctuate about 100 or so RPMs up and down quite a bit like the converter was locking/unlocking constantly.
Burning Brakes
Joined: Jan 2020
Posts: 808
Likes: 399
From: NW Georgia
Sounds like the engine going from V8 to 4 cylinder mode, would be easily fixed with a Range Device to keep it in V8 mode all the time. Before time to return it, I would get it out and drive it to try to make it do it again and monitor the indicator to see if it is going in to 4 cylinder mode. Common problem on all GM vehicles with AFM, I think if you set the car in Track mode and maybe even Sport mode, the car will not go into 4 cylinder mode. If that is not the problem, I would probably return it while I could.
Last edited by seniorstorekeeper; Jun 22, 2021 at 10:05 AM.
Le Mans Master
Joined: May 1999
Posts: 6,517
Likes: 1,304
From: Windermere FL
In most cases, but not all, the triple flush coupled with a Range device will cure the issue. But it is not 100% GM waited out the warranties to expire. You have a sure way of a 100% fix - return this one and look for a M7 or something else.
Instructor
Joined: Aug 2015
Posts: 115
Likes: 31
Sounds like the engine going from V8 to 4 cylinder mode, would be easily fixed with a Range Device to keep it in V8 mode all the time. Before time to return it, I would get it out and drive it to try to make it do it again and monitor the indicator to see if it is going in to 4 cylinder mode. Common problem on all GM vehicles with AFM, I think if you set the car in Track mode and maybe even Sport mode, the car will not go into 4 cylinder mode. If that is not the problem, I would probably return it while I could.
