State of the A8 transmission?
02-28-2018, 08:47 PM
#21
Burning Brakes
17 early build and it's really silky smooth. Don't have many miles yet. Not going to worry. Drive it very spirited. I do have a 17 srt grand Cherokee and it's eight speed is much more aggressive.
02-28-2018, 09:21 PM
#22
Le Mans Master
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St. Jude Donor '15-'16,'18
02-28-2018, 10:01 PM
#23
Race Director
Or perhaps there are a lot of A8 issues but some people just keep telling everyone they don't exist?
Perhaps the way to get GM to actually change what it does is to stop buying their cars?
Buy hey, some people will keep buying no matter what garbage you give them. Wait, was I talking cars or politics...same thing.
Perhaps the way to get GM to actually change what it does is to stop buying their cars?
Buy hey, some people will keep buying no matter what garbage you give them. Wait, was I talking cars or politics...same thing.
The highest estimate I've heard is 5%. If that's true you have to be pretty unlucky to get one with issues, however even a 5% defect rate is unacceptable IMO.
I assume by your comments you are one of the unlucky ones?
I totally agree that the only way to get GM to improve quality is to stop buying the C7. However that will never happen because "haven't you heard" the C7 even with it's A8 issues, the poor body panel fit, the cracking wheels, wabble sound in the rear, poor carpet quality and poor sound insulation is still the best value in high performance sports cars in the world.
Last edited by Kevin A Jones; 02-28-2018 at 10:15 PM.
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JumpingJackFlash (03-01-2018)
03-12-2018, 12:08 PM
#25
There's a sticky with forum data compiled on the top this page showing a shockingly high number of issues (31%) of all 15-17 models, with 15 being the highest and trending down each year until 17 (18%).
I'm certain the "no problem" response is under-reported because those typically get reported far less often in forum polls, but it's clearly higher than it should be.
I'm certain the "no problem" response is under-reported because those typically get reported far less often in forum polls, but it's clearly higher than it should be.
03-12-2018, 12:54 PM
#26
Instructor
There's a sticky with forum data compiled on the top this page showing a shockingly high number of issues (31%) of all 15-17 models, with 15 being the highest and trending down each year until 17 (18%).
I'm certain the "no problem" response is under-reported because those typically get reported far less often in forum polls, but it's clearly higher than it should be.
I'm certain the "no problem" response is under-reported because those typically get reported far less often in forum polls, but it's clearly higher than it should be.
03-12-2018, 01:03 PM
#27
Le Mans Master
Buddy of mine has an early A8 '15... has about 60K miles on the car - took it to Europe for a year and drove it all over.... zero problems.
03-12-2018, 01:09 PM
#28
Yep, according to the forum data, 69% haven't had a problem.
03-12-2018, 02:53 PM
#30
Cruising
I had problems just after I purchased my 15 used. Had the flush procedure with no success and then the TC replaced. No longer have the sensation of driving on a rumble strip but still have the 100 rpm fluctuation on the tach while cruising. Extended my warranty as the original would have expired in April of this year. As stated earlier in the thread, living in the North meant that the car was put away in early November. I believe the drop in comments in regards to this situation is directly related to the fewer number of cars on the road for the last few months. Have already advised my local GM dealer that I will be back in the spring.
03-13-2018, 07:13 AM
#33
Le Mans Master
03-13-2018, 01:58 PM
#35
Le Mans Master
03-13-2018, 02:01 PM
#37
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St. Jude Donor '15-'16,'18
The GM A8 tranny should have been a strong point for the C7. Unfortunately along with AFM it has proven to be probably the #1 weak point. GM should outsource their automatic trannies to ZF.
Last edited by rmorin1249; 03-13-2018 at 08:16 PM.
03-13-2018, 02:07 PM
#38
2016 Z06 (March 2016 build and delivery) using Range module and the transmission is fine. Shifts smoothly under light load with quick and firm shifts under power just as it should. I prefer to be driving rather than waiting for what is next.
And for the Z06 I could care less about having 10 gears or even 8, a six speed that shifts as fast as the 8L90 would have been fine for that application. There are definitely tailor made applications for an 8 or 10 speed like a pickup used for towing where a wider selection of gears means a wider choice of road speeds where the engine can run a peak horsepower for pulling grades at maximum speed but for a car unless it has a very "peaky" torque curve it doesn't provide a huge benefit.
Now when a CVT becomes available that will efficiently and reliably transfer a sustained high power level that will be worth having, especially if combined with AWD. It would let the engine run at peak horsepower providing the maximum sustained acceleration possible from that powertrain and set of tires.
And on edit: If I were keeping my C7 for a very long time I would be far more worried about failures from the AFM system causing severe engine damage rather than issues with the A8. Anyone who plans to keep their C7 as a family heirloom should seriously consider having a regular cam and lifters along with the required tune put in once it is out of warranty. That is true whether you have a M7 or A8.
And for the Z06 I could care less about having 10 gears or even 8, a six speed that shifts as fast as the 8L90 would have been fine for that application. There are definitely tailor made applications for an 8 or 10 speed like a pickup used for towing where a wider selection of gears means a wider choice of road speeds where the engine can run a peak horsepower for pulling grades at maximum speed but for a car unless it has a very "peaky" torque curve it doesn't provide a huge benefit.
Now when a CVT becomes available that will efficiently and reliably transfer a sustained high power level that will be worth having, especially if combined with AWD. It would let the engine run at peak horsepower providing the maximum sustained acceleration possible from that powertrain and set of tires.
And on edit: If I were keeping my C7 for a very long time I would be far more worried about failures from the AFM system causing severe engine damage rather than issues with the A8. Anyone who plans to keep their C7 as a family heirloom should seriously consider having a regular cam and lifters along with the required tune put in once it is out of warranty. That is true whether you have a M7 or A8.
Last edited by NSC5; 03-13-2018 at 02:18 PM.
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bigsapper (03-14-2018)
03-13-2018, 02:20 PM
#39
Instructor
I have a c7 a8, had the wabble problem from the first month i had it. Been to the shop 5 times, tripple flushed the rear end twice, still has the wabble noise. Going for a lemon law act, after three times for the same problem, they will file, they are also buying back the car because they do not know how to fix it
03-13-2018, 04:13 PM
#40
Instructor
A8
My 16' has been in the shop 145 days total since I bought new in August 16". Just a few thousandths off will cause the crankshaft to fail. Mine did. I will be giving up on Corvette. Lemon Law is working, should be finished up in a few days.