Dif

So far my A8 is working great and I feel for those that are having problems.
It doesn't make it OK, but when considering the number of A8 transmissions produced it's a relatively small number with problems.
For the sake of conversation:
My background is Precision tool making and design.
I've thought to myself how can they test the hell out these cars and then still have some of these problems.
With more thought and looking at what I've seen over the years, you have to consider everything that goes into design and manufacturing.
The main thing is the supplier and the Quality and repetitive tolerances of parts made for the design of said item, in this case the A8 Transmission.
The design can be spot on but, if the parts are not, there lies a problem with the final product, and visa versa
So again, how is it these cars are tested to the limit before mass producing them and still have problems.
IMO it's because when they take the parts and use them in said item, they pick and choose parts that meet the designed tolerances for the test mules.
But once production starts there's always those parts in the mix that slip through and not quite the quality or within tolerances they were designed to be.
Sure the parts are inspected for quality to ensure they're built to the design print and specified tolerances.
But, Nobody checks Every Single Part, they check only so many, as in 1 out of 10 or whatever.
Now multiply this and look at Every other part needed to design and build any vehicle of any Brand vehicle, add human error, and it's amazing they don't have more problems then they do.
On another note, in my experience, you also have to consider what happens to the product when it gets in the hands of the Consumer
That IMO is the true test of any product and have to literally design things to be Idiot proof.
And with that in mind, it can be damn near impossible
Just my thoughts for the day for what it worth
Wishing everyone a Happy 4th of July Holiday and trouble free motoring

JoesC5

This forum represents a very small portion of the A8's usage. Go to the truck forums and the Caddy forums and read what they are saying about the A8.

The A8 problems are not restricted to just the Corvette.

\Boost Monkey/

That's a great post and all...


















But the main flaw/problem with the A8 is the design (namely of the torque converter), not the parts or quality of the parts.


The other also being a design (software) issue (learning process of the TCU).

MikeLsx

Been on lots of car forums.

you rarely hear about problems with BMW DCT or Porsche PDK.

So i think the A8 overall is less reliable vs other makes.

\Boost Monkey/

Agree, but:


I think the A8 is fine now that the issue(s) has been resolved, but the fact remains that the whole 15' model year and a quarter or so of the 16' model have the flawed version.

JoesC5

But we don't know if the issue has been fully resolved. We have seen posts on this forum from A8 owners that had the stator support replaced and it didn't completely resolve the problem. In a couple of the posts, the tech that worked on the car talked to GM engineering, as the issue wasn't resolved with the TSB replacing the stator support, and the tech was told that GM is still "working" on a fix.

69L79

IMHO, the A8, thus far, has been a weakness in a great generation of Vettes. To those of you with a perfect performing A8s . For those with chronic problems, you deserved better for your money.

\Boost Monkey/

This is true, but in the one post I have seen the stator support resolved the first of day hard shift, but the jolting 1-2, 2-1 remained and we are not sure yet if that is a result of the work itself or the solution not working.


Others (one I know for sure) has posted a new TC solved his issues completely. So, I can agree we don't know for sure, but only time will tell for the later 16' and 17' guys.


So far, I have not seen a post from anybody with the revised version.

Rebel Yell

I've got one of those A8's. It works fine now, but has to few miles to make an educated guess of it's reliability. Fingers crossed though.

Ernest_T

I don't know if my A8 is the culprit or its an issue with AFM, but my car shudders continually in V4 mode. GM says sorry, we don't have a fix for it now. Not a happy camper.

bbcb

and you except that for an answer ??

Dif

and don't get me wrong, I do think things could have/be better.
But the Torque Converter is a part, and from what I've seen, those who had it replaced with a newer version report good results.
Same with the O-Ring thing, it helped some and others not.
Not to argue the point, but if it's simply "The" Torque converter, ALL the A8 would have this problem.
In other words, some are good and some are not, as to my thoughts that not all the parts/Torque Converters were created equal.
Or maybe it's the Parts the Torque Converter is hooked up to ??
Software, same thing, needs to be tweaked or whatever, works on some and not others but who knows why.
I'm not defending the A8 saying it doesn't have problems ... I agree it's not good that they do have problems.
It's in the back of my mind if, mine will go South at some point

At this point it doesn't seem to be just one thing, and even though there seems to be more A8's with problems then we/I probably know about, it's still not all of them.
If it was a definite pin point problem with design or parts, then All of them would have a problem.
Or maybe I'm wrong
Again, not defending anything, just throwing my thoughts out there as to why and my experience designing and building mechanical things.
Best laid plans of mice and men, Murphy's law etc etc etc
Mostly we see Bashing, sometimes for good reason, other times just because.
My thoughts were more about how or why things can go wrong and it's usually anyone's guess until something definite is revealed, or a combination of things

C7DriverOnt

Seems each time a new generation of trannies come in there are teething problems. Seen it so many times over my last 50 yrs of buying cars that I just try to avoid them. If I was in the market for a 2015/16 it probably wouldn't have stopped me from buying one (that's why we have warranties) but since I was looking for a '14 and had heard there was a 8 spd coming in the back of my mind I thought having the older 6 spd will likely be one less hassle.

Dif

Does it go away when in V8 ?
Do you have the Z51 suspension ?

Elohim1

Did not realize there was s problem, glad mine was built 5/16.

20171LE

That's because PDK is the best transmission in the world.
Remember all the people who got crucified on here for slamming the A8 upon release and for saying GM's comparisons to PDK were absolutely ridiculous??

It's time for GM to step up and just pay a vendor to provide a DCT that meets Corvette spec.
All the excuses are transparent and weak, especially with $100k+ MSRPs.

joemessman

I can understand the frustration. But allow me to ask this question. If it was a design problem, wouldn't all the transmissions have the problem issue? I would think that if you had a "parts" problem in manufacturing, that all transmissions would also be bad. But.....if some parts were manufactured out of spec or not cut properly you would see what we have here. Some transmissions are fine, while others are faulty because of a poorly manufactured part. What do you think about this?

\Boost Monkey/

Totally understand, I am in the engineering/design field as well so I like good discussions on these matters.


But see, the tell-tale thing to note here is a revised design with new part numbers, signaling an inherent flaw in the original design.


The number of cars affected is irrelevant (for sake of our discussion) because the parts are as-designed and a flaw in the manufacturing or QA/QC process of the parts (if this was causing the issues) or just a fluke pre-mature natural failure would result in replacement of like-in-kind parts to solve the issues, not newly revised parts like we are seeing.


I disagree completely with all A8's seeing failures because of a design flaw. A design flaw that apparent would have been caught in the testing/vetting phase of the design process. The failure rate here is just low enough that GM was not able to find the issue prior to release of the design...This happens all the time and is why parts are constantly revised during the generations. The reason that this is only occurring in some cars is unknown to the public, but the fact remains that we know GM has identified a design flaw and has attempted to rectify the issue with a re-design.


This happens...Think ignition switches.

MikeLsx

Thats what i am saying.

I remember them saving a DCT cant handle the torque of a Z06. But so many high powered cars are using some kind of DCT.

the PDK is such a proven transmission.

bbcb

GM monitors this forum ...lets wait for their answer ...yeah right !!