IA_Stingray

This only happens in drive, not in manual mode. Is this an example of the TC issues I've seen described?

ddelallata

That's exactly what my 2017 GS is doing. Others here have said the shudder is around the corner. I'm hoping that I can soon find a dealer that'll try the new triple ATF flush procedure.

djnice

That looks like the TC issue. I am basing that on what I have seen others post over the last 6 months on this forum and the camaro forum.

Red C8 of Jax

That is one of the symptoms of a failing torque converter. I had the same symptom as you and my dealer replaced my TC. I also had the shuddering and feeling like you are on a rough road when you are on a smooth surface. Make sure you go to a dealer who has replaced TC's. The first dealer I went to said I had no transmission problems. If you don't have the shuddering now, you will and it will get worse. I think they are now just changing the transmission fluid three times to correct this problem. Good Luck on that fix. If it doesn't work, I would insist on a new TC. I have had no further problems after the TC was replaced.

IA_Stingray

Thanks for the feedback, guys.

ddelallata

I see yours is a 2017 with very low miles. What is your build date?
Mine is 8/16

IA_Stingray

Sorry, I don't recall the build date but I bought it last year, as soon as the GS hit the lots, so it was early. I took the video as I was headed to the dealer to trade it in. Soon I'll have a 17 Z06 and I hope like hell it doesn't have any issues. I'll be sure to put it in drive and watch the tach before I take ownership.

djnice

Sounds like you have a good game plan. One thing I did and I have no idea if it made a difference, but mine does not exhibit the problem. I drove the car in M during break in so that I could control engine load. I did make some quick accelerations in D, but I never let it go in V4. Then after 500 mile I mostly drove in M, especially when cruising. Now when I drive in D there is no problem. Maybe it will just take longer to show up.

IA_Stingray

When I took that video, that was only the second or third time it had ever been in drive. I always use M.

joemessman

Hope it is fixed soon. For you experts out there, why in the world would just changing the fluid 3 times repair the TC?

djnice

Interesting, its crazy to me that some have the problem and others don't.

I am sure more experts will speak up. All I have are guesses and theories. LOL. I wish GM would share technical details. My guess is to flush debris. Some say they are putting in different fluid. I don't think that's the issue. Debris either during the build or coming off the TC clutch. My theory is debris is preventing the TCC to release and engage correctly. For normal use there is probably nothing wrong with the TC. The problem exhibits when creating rpm slip to mitigate V4 mode vibration.

qwksvt

They are changing fluid type and many claim the original fluid lacks the proper properties to control TCC shudder

YO-EL

Maybe buy a handheld tuner & stay in V8 all the time..

cib12

i did an owners chat with GM. There is a dealer look at on the A8, not yet a recall. The chat person will contact your dealer with this.

VLADIE22

mine fluctuated badly on the highway. I bought the Range AFM Disabler and now the RPMs are steady at all highway speeds,including when using cruise control . There has to be some thing with the V8/V4 transition that is the cause of the problem.

Always Red Dave

Build date is on the inside of the drivers side door and Good Luck you guys with your 2015-2017 A8"S you deserve it!

KemahGT

Correct. I sure hope it is the fix. I'm still waiting. My local dealer can't be trusted to change my oil and I'm not ready to drive much more to get it done. I feel for anyone that lives in the middle of nowhere and must drive some crazy distance to get warranty work done.

jivor

I had the exact same thing. It would be nice for a thread merge, you'd get a lot of insight. Mine was a 2017 GS built in June. The tach would oscillate around 150 rpms in V4 mode; I got the TC replaced and fluid flush under warranty and noticed an immediate decrease to 50 rpms and now after nearly 2K miles, the oscillation is almost unnoticeable. Fingers crossed.

Jay_Davis

Its funny, this is the only problem my trans/TC hasn't had.

KrikGS

Your fluctuation really isn't that bad, YET. Give it time. It will only get worse. Mine started off like yours (less than 100 rpm fluctuations) but with no shuddering. At the time, I thought it was weird but maybe a function of V4 mode that I wasn't used to seeing. After a while, the RPM jumps got worse and increased to 100-200 rpms. Then came the dreaded shudder.

Find yourself a good dealer that has experience with Corvette TC issues. Good luck!