2016 A8 Z51 with 4090 miles. I feel a "shuttering" feeling while driving at consistent cruising speeds. This came on gradually and seems to have gotten worse. I have not been on the forum in awhile, so maybe this same topic has been discussed, but in a search, I could not find it.

I brought into my local dealer, they said it was "common" and needed a "flash" for an update. While there, I had the air bag recall issue taken care of, and the complimentary oil change. They said they test drove it, and everything checked out. I did notice the shifts from gear to gear appeared smoother, however after about 10 minutes of driving I felt the first shutter. Drove it yesterday on a very smooth and level road. At 62 mph, the rpm's are @ 1500. Then comes the shutter that lasts about 2-4 seconds (some are worse and longer than others) during that time, the tach clearly drops 200-300 rpms and the needle fluctuates in conjunction with the shutter as the motor and drive train seem to fight through the problem. It is annoying as hell, and can't be a good thing as it feels the entire drive train is struggling during the problem. It is not a minor shutter, pretty severe, I counted 14 occurrences in the 4 mile run. Made another appointment for this Friday morning. I was told they will "take care of it" any ideas? Anyone else experience this problem. I use the word "shutter" because that is the best description I can think of, it is a very pronounced way beyond vibration that you feel in the entire car, seat, etc. In fact my wife said "what was that?" when it first occurred. 7th and mostly 8th gear seem the worst, but I seldom stay in 6th and below the way the trans shifts.

 

sounds like your car needs a new torque converter.

 

Yup, likely torque converter.

See TSB in post 15:

https://www.corvetteforum.com/forums...-shudders.html

 

No doubt, you need a new torque converter, mine did the same thing. Take it to a dealer who has replaced torque converters before. The first dealer I went to said everything was normal. Took my car to a dealer who had replaced quite a few TC's and in 5 min they said I needed a new TC.

 

What is your build date?

 

Consider taking it to Stingray Chevrolet in Plant City.
One of the members just had their transmission Repaired there. While others are talking about weeks they were done within just a couple of days, or less, If I remember correctly.

 

Why do the RMPs drop if it's the TC?

 

Yours still working good after the TC swap ?

 

Many threads on this issue and mine is in the shop now for a TC replacement. Do a search, research thoroughly, and have your info together before approaching the dealer again. One important document is PIP5337E, which will probably sound familiar when you read it. Note that the TC part # 24279495 (Rev. 2) stated in that document has been superseded by 24280631 (Rev. 3). Make sure they use the latest TC revision!

Yes.

Need a reflash? Doubtful unless you're having shifting issues. Fix the shudder? No. Been there, done that. A TC replacement is the current "fix," but they're on revision #3 of the TC now and the first three (original and revs. 1-2) have not been the fix for all vehicles. Some are on their third TC and a few 2017 owners are reporting TC problems. I'm hoping the latest revision is the magic bullet but am not optimistic.

 

It's a feature called "lock Up". Simply put, the TC transfers the power from the engine to the transmission hydraulically, meaning that the engine is not connected directly to the transmission on automatic cars. Rather, inside the TC you have two turbines, or fans, facing each other, submerged in transmission fluid, so when the engine side starts turning its fan, it blows the fluid onto the fan connected to transmission and subsequently starts turning that fan and moving the car. Much like blowing on a pinwheel. But since the engine is not directly connected to the trans, you can completely stop the car without stalling the engine. Needless to say, there is a huge loss of power due to the inefficiencies of this hydraulic connection. This is where "lock up" comes in. On most cars, when the transmission senses that you are in top gear and traveling at a constant 45+ MPH, it will automatically bypass the fans and connect directly to the engine, ergo the RPM drop as if you had another gear. Soon as you drop speed or accelerate to pass, it disengages until you resume a normal cruising speed again. Reason for the system is mainly fuel economy. The way the system is designed is that there is a clutch and plate in the TC that engages and disengages and the shutter is normally from a bad clutch or the "lock Up" engagement coming in or out at the wrong times. I had just purchased a new Chevy Tahoe and noticed at certain speeds and rpm, there is a slight vibration which I think is the TC coming in too early at lower gears, and I believe the car has the same 8L90-E A8 as the Corvette. So I think GM has some engineering and warranty work to do.

 

Yes, the transmission has been flawless. My TC was replaced February, 2016 and I have put approximately 14K on the car since the new TC.

 

Curious, when was Rev. 3 released for use?

 

Roughly about 30 days ago.

 

Was able to record the shuddering noise with my phone. Is this what people are hearing? I'm coasting, then gently accelerate and the noise is constant until I go back into V8 mode.

 

If you are observing an RPM change of over 50 RPM and/or observing a shaking in the steering wheel or seat much like driving over a rough road it is extremely likely you have a TC problem. It is likely the RPM changes and shaking will go away when you put it in V8 mode.

Refer your dealer to bulletin 16-na-175. It seems that currently the first fix is to do a "triple flush" and use Mobil 1 synthetic fluid. Had it done to mine last month and it has been good since.

RIRENTERC6 - Just by looking at your RPM changes, you have the problem. Have the dealer fix it.

 

Looks like a problem with the belt tensioner that other Z06 owners have been having.
Mine had the TC Shudder and it didn't feel or sound like that.

 

ShuTTer is something found in a camera or beside a window. ShuDDer is a vibration or shaking.

I just can't understand why GM even bothered trying to meet their CAFE goals by putting the AFM and destined-to-fail TC lockup clutch arrangement in the Corvettes. They add several thousand dollars to the purchase price, nobody really wants them, and for sure nobody wants all the headaches they've caused. Look at all the lost sales, unhappy customers, and added warranty expense they've incurred.

C7 buyers would have been way better off just paying the gas guzzler tax on every car.

 

they completed the flush 2 weeks ago. They are now going to look into replacing the TC. I'll keep you all posted.

 

Look into this TSB
http://www.corvetteactioncenter.com/...-afm-1357.html

 

Is there an updated bulletin that includes 2017 models? I have a 2017 Grand Sport (build date 7/28/2016) that exhibits the RPM variation with AFM active (see post 305 here)

I don't notice any symptoms except for the RPM variations but this can't be a good thing.

John