C7 transmission surge
03-29-2017, 12:26 AM
#62
Instructor
Thanks for the thought. I did have the foresight to purchase a 100,000 mile warranty when I bought the car.
03-29-2017, 02:13 AM
#63
Melting Slicks
Having the issue occur in M mode is pretty rare. Do you mind describing the symptoms in M mode?
03-29-2017, 12:19 PM
#64
Instructor
03-29-2017, 12:46 PM
#65
Sorry to hear about your A8 issues. I have a 2015 Z51 3LT that has been fine. Had a early on shift bump on cold start but that resolved itself. This is Corvette number 6 over 40 years for me and I love the car. Got another year on the 36 mos. bumper to bumper and 3 more years on the drive train. While a very nice car with low miles and highly pampered it will never be worth more than it is today. All things considered I am thinking about trading it back in to the dealer. They have expressed interest. Maybe time to cut the loss and move on. If the dealer is fair I might pick up a 2017 Grand Sport hopefully with no trans. bugs. If not I will just have to make do with a SL Benz. Anyone see my point?
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Spinny (03-30-2017)
03-29-2017, 03:23 PM
#66
Racer
03-30-2017, 01:13 AM
#67
Melting Slicks
03-30-2017, 08:41 AM
#68
Instructor
03-30-2017, 10:48 AM
#69
Platinum Supporting Dealership
Check the Corvette Action Center's Knowledgebase for any service bulletins that may pertain to this issue:
http://www.corvetteactioncenter.com/...ansmission/14/
http://www.corvetteactioncenter.com/...ansmission/14/
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Spinny (03-30-2017)
03-30-2017, 11:07 AM
#70
Instructor
Check the Corvette Action Center's Knowledgebase for any service bulletins that may pertain to this issue:
http://www.corvetteactioncenter.com/...ansmission/14/
http://www.corvetteactioncenter.com/...ansmission/14/
03-30-2017, 03:48 PM
#71
I always do that too. On most occasions the SM tells me that he has to find the TSB in his database before he can do anything and won't even look at my copy. One dealer asked me if they could make a copy of a TSB because they knew nothing about it. I just printed mine off of the internet straight from GM guys. Why do I have more information than a dealer does?
03-30-2017, 11:19 PM
#72
Melting Slicks
Interesting, I see there is a new service bulletin and this shudder can be two different issues. Compare 16-NA-175 to PIP5337E.
16-NA-175 this calls for three fluid flushes. Appears to describe a steady shudder under light load and does not talk about RPM fluctuation. It can happen in either AFM mode, but I am not sure that applies to all cars. Reason I say that is the test procedure table says the PicoScope test is to be done in V4 mode for the Corvette, but V8, etc. for all the others.
PIP5337E says to replace TC if you have rpm fluctuation greater than 10 rpm. The shudder appears to occur only at TCC apply so I think this would be an oscillating shudder. Oscillating because as I understand it TCC apply cycles constantly during V4 mode and that's why you get rpm fluctuation.
Since 16-NA-175 does not address RPM fluctuation. If you have RPM fluctuation it seems to me they need to follow PIP5337E and replace the TC. If they follow all the test procedures in these two service bulletins they should know the three flush is not going to work. GM should clarify this.
16-NA-175 this calls for three fluid flushes. Appears to describe a steady shudder under light load and does not talk about RPM fluctuation. It can happen in either AFM mode, but I am not sure that applies to all cars. Reason I say that is the test procedure table says the PicoScope test is to be done in V4 mode for the Corvette, but V8, etc. for all the others.
PIP5337E says to replace TC if you have rpm fluctuation greater than 10 rpm. The shudder appears to occur only at TCC apply so I think this would be an oscillating shudder. Oscillating because as I understand it TCC apply cycles constantly during V4 mode and that's why you get rpm fluctuation.
Since 16-NA-175 does not address RPM fluctuation. If you have RPM fluctuation it seems to me they need to follow PIP5337E and replace the TC. If they follow all the test procedures in these two service bulletins they should know the three flush is not going to work. GM should clarify this.
Last edited by djnice; 03-30-2017 at 11:20 PM.
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Spinny (03-31-2017)
04-05-2017, 09:28 PM
#73
Instructor
Update II Got a call from the dealer today telling me that the three flush "fix" had been competed and my car was ready to be picked up. I inquired as to whether the flush procedure has solved the problem or not and was told, rather sheepishly, that it seemed somewhat better, but that the full efficacy of the procedure cannot be assessed until the car had been driven 200 miles after the procedure was completed. I immediately returned to the dealer, picked up the car and drove 200 miles. Sad to say, but not unexpected, the shudder problem is exactly as it was before the triple flush was done. After my 200 mile drive, I returned to the dealer and told them that the "fix" had failed. They had the same technician who drove the car when I first brought it in with the problem drive the car and he confirmed that the shudder was still present. The car is back at the dealer and I have my loaner Malibu. They tell me that they must now report all this to GM and obtain authorization to replace the TC, a process that will take one to two weeks, assuming the necessary parts are not on backorder.
Got the car back from the dealer today with a new TC installed. (Yes, they used the latest version of the TC and the new fluid.) So far the problem seems to be resolved. Let's hope that it remains so. Thanks again to all the Forum members for their suggestions, commiseration, and helpful comments.
04-06-2017, 11:17 AM
#74
Drifting
and I want to trade up but I am holding on to my A6 until A8 problems are fixed or a A10 arrives. Also their was over 24,000 A6 2014 C7'S and you very rarely hear of any problems with the A6. Good luck OP!Not to be an alarmist Dave, but what has GM done to make any of us think the A10 won't be as problematic as the A8 it's replacing?
04-06-2017, 11:18 AM
#75
Drifting
Seems GM has automatic transmission issues across the model lines. My 2016 Colorado (six speed) has shifting issues that require driver intervention (adding power or reducing power as appropriate). Shifting from sixth down to second or third is horrible and the transmission seems to get mixed/hung up in the process (much discussion on the Colorado Forum on this very issue). Seems there are just to many gears and it takes time for the transmission to acquire the appropriate gear (transmission is shifting all the time and I only have the six speed). I can't imagine having an eight/ten speed transmission. My Corvette has the bullet proof M7.
I was thinking about a Colorado, but the 2017 got AFM and a new 8 speed auto transmission. Fool me once, shame on you, fool me twice...
04-06-2017, 11:23 AM
#76
Drifting
You are certainly correct from a rational point of view, but I am now so fed up with the matter that it is difficult to be completely rational about it. As long as the shudder persists, I don't want to drive the car and really don't even want to look at it. To do either just upsets me. Call me crazy if you wish, but that is just the way I feel about it. I can see why some owners just sell or trade their Vettes at a loss rather than deal with the BS GM makes one go through just to get the car perform as it is supposed to. GM seems to have the rather dubious talent of turning a pleasure into a nightmare. Thanks, Mary Barra. I am so glad we bailed you out of bankruptcy.
Now, I'm close to being able to contemplate another C7, this time a manual.
04-06-2017, 11:25 AM
#77
Drifting
Interesting, I see there is a new service bulletin and this shudder can be two different issues. Compare 16-NA-175 to PIP5337E.
16-NA-175 this calls for three fluid flushes. Appears to describe a steady shudder under light load and does not talk about RPM fluctuation. It can happen in either AFM mode, but I am not sure that applies to all cars. Reason I say that is the test procedure table says the PicoScope test is to be done in V4 mode for the Corvette, but V8, etc. for all the others.
PIP5337E says to replace TC if you have rpm fluctuation greater than 10 rpm. The shudder appears to occur only at TCC apply so I think this would be an oscillating shudder. Oscillating because as I understand it TCC apply cycles constantly during V4 mode and that's why you get rpm fluctuation.
Since 16-NA-175 does not address RPM fluctuation. If you have RPM fluctuation it seems to me they need to follow PIP5337E and replace the TC. If they follow all the test procedures in these two service bulletins they should know the three flush is not going to work. GM should clarify this.
16-NA-175 this calls for three fluid flushes. Appears to describe a steady shudder under light load and does not talk about RPM fluctuation. It can happen in either AFM mode, but I am not sure that applies to all cars. Reason I say that is the test procedure table says the PicoScope test is to be done in V4 mode for the Corvette, but V8, etc. for all the others.
PIP5337E says to replace TC if you have rpm fluctuation greater than 10 rpm. The shudder appears to occur only at TCC apply so I think this would be an oscillating shudder. Oscillating because as I understand it TCC apply cycles constantly during V4 mode and that's why you get rpm fluctuation.
Since 16-NA-175 does not address RPM fluctuation. If you have RPM fluctuation it seems to me they need to follow PIP5337E and replace the TC. If they follow all the test procedures in these two service bulletins they should know the three flush is not going to work. GM should clarify this.
Last edited by Ernest_T; 04-06-2017 at 11:26 AM.
04-06-2017, 12:16 PM
#78
Melting Slicks
Good point I forgot about the 10 RPM is slip not fluctuation. However, the PIP5337E says the condition observed by the owner is "excessive engine RPM fluctuation that may be described as frequent tachometer needle movement". Where as 16-NA-175 does not have the RPM fluctuation condition, only shudder. So they don't say the amount of tachometer needle movement that is allowable.
04-15-2017, 10:32 AM
#79
Took my 2015 corvette to dealer concerning 8speed aut transmission surge. After verifying the problem was shown a gm service advisory that says to tell the customer that this is normal. My car shifts rough and any time it is in a pull it surges or jerks. The advisory also uses the word shudder. According to the advisory this is a also a problem with camaro and Cadillac. Has anyone else having this problem gotten any help from gm or dealer. My car is getting worse and this is the second time I have been told that this is normal operation. I think it is time gm stepped up and fixed this and quit making excuses.
08-28-2017, 07:56 PM
#80
I just dropped off my '16 C7 Z06. Dealership will be completing triple flush tomorrow. Car has 14k miles. Surging/rpm fluctuations when car is in V4 mode. Keep you all posted on outcome