Richard Ames

Flutter Back after Triple Flush 7/28/17 2015 CP Z51 19000 miles. Back to the dealer Thursday

Update turned out to be engine misfire and cylinder deactivation codes and not torque converter.

NSC5

Not surprised, magic potions only work in JK Rowling's books.

A new converter and a Range module or manual mode shifting to avoid V4 operation and a recurrence of the problem are about the only real cure at the moment.

I love the performance of the A8 (8L90) in my 2016 Z06 but it will never see V4 operation.

I was seriously considering a GMC 1500 series pickup this time since it is available with a crew cab and standard bed now but with all of the V4 mess it looks like another 2500HD with Duramax for me. I guess the extra profits GM makes from that pickup will help them cover torque converter replacement costs for others. Given the various risks of problems I would rather chance problems with the diesel emissions system in order to avoid V4 mode issues and the Allison 1000 transmission is about as close to bullet proof as you can find.

Zhuskers1

I purchased my C-7 after long relationships with Porsche and BMW. I would agree with your comments on dealer support. I am blessed with a great dealer AND i have a 2014 without an A8 tranny. Just starting to get the bug to trade....based on these issues -- a new C 7 will not be on the list.

Chafey69

[QUOTE=mountainears;1595347037]I'm not sure there is enough evidence to warrant putting a purchase on hold, but do what you feel is right :-)

If I was buying now and not totally interested in a M7, I would still consider an A8. There are TONS more people that have not had a problem than have had a problem.

I'd purchase an extended warranty for sure, once I got towards the end of the factory warranty to protect myself. But I wouldn't let the issues going on get in the way of the purchase

Chafey69

So it sounds like the problem is stemming from the continual transition between V8 to V4. Is it correct in saying that the only way to avoid this problem is to keep driving the G S C E in manual mode?
I haven't noticed if there is a certain build date where this problem seems to appear and disappear. What are your thoughts on this?

motorman1857

I don't think GM has a clue what the real problem is. It's not just Corvette's it's all GM vehicles equipped with the A8. From the PU's to Camaro's. Check their forums. So right now, it's a crap shoot with any A8 Gm car.

iclick

It occurs while in AFM (V4) mode only. I don't think the V4-V8 transitions have any causal relationship with the problems, but rather what's going on while in V4 mode (micro-slips, increased vibration, etc.). I'm not sure anyone, including the A8 eggheads at GM, know the causes or how to fix it. Incidents have dropped off over time, but that could change as 2016- cars compile more miles.

As Motorman said, it's a corporate issue, not just one linked to Corvettes.

Manual mode or a Range module, but the latter may have side effects in some cars (e.g., codes). Mine got worse over time, starting on Day 1, which would lead me to believe time and/or mileage is a factor. I didn't go for the Range device because of reported issues and the requirement to unplug or switch off after each drive to avoid electrical drain. When it got really bad I used manual mode only while waiting for the dealer to dilly-dally and decide what to do, but finally had the TC/flush job done last Feb. They used fluid #19353429 and TC #24280631, which at the time were the latest part revisions. I haven't seen anybody report failures on cars getting the full TC/fluid replacement using these part numbers, which may be a good sign.

lancelot1

A number of posts in this thread have raised the question of why GM does not provide a different trans or allow disabling of afm. The reason, I believe , is related to emission and fuel economy certifications. They in essence would be violating federal law. Just like adding aftermarket headers that impact the oem catalysts. Legally you cannot alter any component that impacts the certification process.

Preston7

I was told today 8/18/2017 that I will be getting my 3rd torque tube! Service said there will be a wait as there is an upgrade.

Heidemarie

Please post the new PN once you get your invoice. Thanks
Heidi
Save the Wave

rmorin1249

Torque tube or torque converter. I haven't heard of issues with the torque tube.

767guy

Preston, do you mean Torque Converter or Torque Tube?

Once you car has been repaired would you please post the part number coming off and the part number going on as well as the part number of the fluid that will be used if required. That would be most helpful for those of us who have been tracking this problem for almost 3 years now.
If I may suggest, ask the service manager in advance of the repairs that you would like that information " for your records"
Last TC replacement on my 2015 the part numbers were not on my invoice and I had to do some running around to get that info, FYI.
Good luck.......

Richard Ames

Update above.

YO-EL

Don't think for a minute GM is truly working on a fix for this..
As demonstrated, they will just try various parts/fluids while the car is under warranty, than delve into the actual fix which may cost them millions in re-working the engine or transmission..

Believe me, if its not a safety issue, this fix isn't coming anytime soon...

1FUNC5

We're you getting a check engine light? Was it missing at all upon idle or just when you were on the throttle?

hanks

I dont know if you can avoid the problem but you can certainly delay it. My 2016 A8 (Sept 2015) build was never in V4 mode after ~400 miles. My vibration developed at around 16000 miles and I noticed it on the highway. When I took it to the dealer and let it go into V4 mode, the shudder during the transition from V8 to V4 was very evident so either I delayed the onset by staying out of V4 mode or I just did not notice it much because I never let it go into V4 mode.

dr4carz

Anyone with a 2018 Gen 3 torque converter part number 24280631 have issues yet????

Richard Ames

Got a emissions light a few days and got it read at a chain auto parts store. It cycled off though so thought nothing more about it till I took it in for service. It was running smooth by the time I got the service point but they drove it in eco mode for 40 and 15 miles tech and then service manager and could not reproduce the problem. Has ran fine since but installing the AFM Disabling Device tomorrow. Some say it makes for a smoother ride.

I also use a Top Tier fuel (Shell VPower) from a station that tests their tanks daily.

Brian Handy

GM approved my full refund buy back. Car still in dealers possession for now 2 months 4th time back. I called the gm customer service number per my service advisor fast forward almost 2 months, approval for full refund. It's really sad, they can't fix it, lemon law attorney can't help when vehicle is at dealer, but God is amazing and this massive debt and stress will soon be over. I've been paying for a car not in my possession but all will be refunded. Sticker was $85k, just glad it soon will be over. Good luck gents!!!

Brian in Bakersfield...

OldJedi

I'm not sure I will fit into your survey. I have a 2015 Z51 Auto. It overheated the first time I took it to the track at about 1600 miles. I brought it back to the dealer and had all the fluids changed, about $475.00 for oil, transmission and diff. I was disappointed that the track star I bought really could not handle the track after all. I currently have about 7500 miles on the car with no other problems but I will not take her back to the track again. Too many stories like the others in this survey that are having serious problems. I put Z06 quarter vents and grill on and she will run all day (11 hours) between 150-160 degrees and 70-85 mph. She is a great GT car getting well over 30 mpg on trips but she is not a track star. Thinking about maybe getting a Porsche Cayman for the track but that is further down the road. Like I said this might not fit this survey but I do thank you for putting it together.