A8 shutter question
Thread Starter
Drifting
Joined: Oct 2009
Posts: 1,385
Likes: 86
From: San Diego CA.
A8 shutter question
I have a 19 GS A8. 5600 miles. I was driving on the freeway and hit an incline. I lugged the car slightly. Not bad though. I felt something odd. The car surged about 6 times. I watched the tach. It rose and fell 100 rpm’s. Is that the A8 shutter? It only did it that one time. Thanks for the feedback.
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
I have a 19 GS A8. 5600 miles. I was driving on the freeway and hit an incline. I lugged the car slightly. Not bad though. I felt something odd. The car surged about 6 times. I watched the tach. It rose and fell 100 rpm’s. Is that the A8 shutter? It only did it that one time. Thanks for the feedback.
Pro
Joined: Dec 2004
Posts: 597
Likes: 24
Mine was doing it at lower and higher speeds. My dealer service dept told me there is a factory bulletin on this and that the first thing they try is a trans service. Flush the trans and converter. They said if that doesn't work there is a new converter coming out in 1st quarter of 19 to fix it. After they serviced mine it went to barely noticeable at all but sometimes a little bit. If what they say about the fix in 19 is true I will get that done if it is doing it at all
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
Mine was doing it at lower and higher speeds. My dealer service dept told me there is a factory bulletin on this and that the first thing they try is a trans service. Flush the trans and converter. They said if that doesn't work there is a new converter coming out in 1st quarter of 19 to fix it. After they serviced mine it went to barely noticeable at all but sometimes a little bit. If what they say about the fix in 19 is true I will get that done if it is doing it at all
Thread Starter
Drifting
Joined: Oct 2009
Posts: 1,385
Likes: 86
From: San Diego CA.
What is interesting about this TSB#16-N-175 you alluded to is that they specify a test to determine if the Torque Converter Clutch is the problem. This test is only conducted in "Eco Mode Only". If the vehicle does not pass the test then the transmission flush is recommended. The TSB doesn't say what to do if they conclude the torque converter clutch is not the problem. Presumably they are replacing the torque converters if under warranty. You would think that everyone should take heed and purchase a Range Tech AFM disabler to disable "Eco Mode".
Safety Car
Joined: Mar 2018
Posts: 4,754
Likes: 1,650
the TSB implies that this condition only occurs in V4 ECO mode. It suggests, if you read between the lines, when this shudder does occur (it is only in ECO Mode" It doesn't imply it happens to everyone.
Last edited by MMD; Nov 21, 2018 at 11:26 PM.
Thread Starter
Drifting
Joined: Oct 2009
Posts: 1,385
Likes: 86
From: San Diego CA.
Oh man. I think I was in eco mode. Long uphill and lugging. Well, I guess the answer is to simply hall ***! Lol. The C6 Z had the valves that fell out and the C7 has the transmission. My C5 was flawless. Oh well. Thanks for the info.
Last edited by vetten76; Nov 22, 2018 at 12:52 AM. Reason: Spelling
Melting Slicks
Joined: Jun 2016
Posts: 2,845
Likes: 521
From: Eastern WA
That is how my 17 GS behaved. Certain speed, certain load and the trans controller would lock and unlock the TC. It will destroy itself if it keeps doing that for long. You need to intervene and change speed, change load, shift to M, use range or get a tune.
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Thread Starter
Drifting
Joined: Oct 2009
Posts: 1,385
Likes: 86
From: San Diego CA.
I just installed the Range AFM killer. Thanks everyone!
Melting Slicks
Joined: Jun 2016
Posts: 2,845
Likes: 521
From: Eastern WA
Congrats. There are some other threads on this topic if you want more info. Seems the trans is tuned to lock the clutch as often as possible and then pulse locking and unlocking to smooth out the transition and improve economy. The V4 mode adds more pulsing of the clutch. My theory is it is needed to regulate load and keep the engine in V4 longer.
Burning Brakes
Joined: Dec 2000
Posts: 993
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From: Cincinnati Ohio
Thread Starter
Drifting
Joined: Oct 2009
Posts: 1,385
Likes: 86
From: San Diego CA.
[QUOTE=1999 White C5 Coupe;1598825083]This is great thanks. My problem now is that I really like the Range thing that keeps it on all 8. The car drives so much better. Gas mileage dropped a little, but it’s still good. Thanks for the fix link.
Pro
Joined: Jul 2016
Posts: 698
Likes: 191
From: N. San Diego-Fallbrook California
Here is the fix: https://gm-techlink.com/?p=11127
Heel & Toe
Joined: Nov 2016
Posts: 17
Likes: 2
From: Auburndale Florida
I have a 2016 C-7 (Z51) and at 4500 miles had the torque converter replaced. It was doing just fine until the other day when the Stutters came back and also it feels like someone is hitting the car from behind every now and then. It doesn't matter what speed 35 - 80 so I'm now getting my second torque converter at 23000 miles. I sure hope this is the last time. I drive mostly in tour mode.
