When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My dealer says they can find nothing wrong with the car and the oscillating tach is normal. I don't think it is, but don't know where to go at this point. They still have it and he read me a GM bulletin about the condition and GM says the oscillation tach and slight vibration are normal conditions in V4 mode..
If your dealer has a 2016 ask your sales representative to test drive it and then check the tach and see if it is oscillating. This is not normal but if you can't feel the transmission shudder I would just wait until you start feeling the shudder in the steering wheel. As I have posted, my first dealer said nothing was wrong with my transmission and the second dealer ordered a new torque converter.
If your dealer has a 2016 ask your sales representative to test drive it and then check the tach and see if it is oscillating. This is not normal but if you can't feel the transmission shudder I would just wait until you start feeling the shudder in the steering wheel. As I have posted, my first dealer said nothing was wrong with my transmission and the second dealer ordered a new torque converter.
I have an early '16 that supposedly has the 'old' trans/converter according to posters here and it doesnt do that as far as I can see. As I posted above the RPM only changes when it switches from V4 to V8 and you cant even tell if you werent looking at the tach.
But its almost impossible to find 10 miles of perfectly level road around here to go 70mph, mine may do it to but I'm not going to drive 200 miles North to find out. In V4 I assume the throttle is moves some to keep the speed up, even on a flat road the wind resistance alone is always trying to slow the car down.
IMO if GM would just give people the ability to shut that stupid AFM off except in ECO like the manual trans cars there would be less complaints
If your dealer has a 2016 ask your sales representative to test drive it and then check the tach and see if it is oscillating. This is not normal but if you can't feel the transmission shudder I would just wait until you start feeling the shudder in the steering wheel. As I have posted, my first dealer said nothing was wrong with my transmission and the second dealer ordered a new torque converter.
Good suggestion .
Before you had you torque converter replaced did you also have the harsh 1-2 shift first drive of the day ?
When was your car built ?
I have taken several road trips on level interstates in my C7. I used to set the DIC so I could watch it transition in and out of V4 mode but I have stopped doing it. Unless I am watching the DIC it is very difficult to tell when my car moves in and out of V4 mode as there is just a very minor shudder that is almost undetectable. I also have an early build 2016 so I assume I also have the "old" A8.
I sure hope these A8 problems only pertain to 2015 A8's and not 2016 A8's. I feel bad for the guys that are having problems with the first year A8 trannys . I will not be trading my 2014 A6 in for at least a 2016 or newer A8 when I do trade in and I am sick of hearing all this shi" that should not be happening with the 2015 A8 C7'S.
You are correct ,it is not normal. My 2015, C7,A8, at highway speeds when operating on a level road in V4 MODE has no vibration and the tach is rock steady unless of course you start going up or down hill.
Maybe a long shot, but perhaps some forum members could take a video of their cars in the same situation as yours that are operating correctly with no rapid fluctuations. You could show that to you service mgr as proof that the fluctuations are not normal.
Also I assume you are using a GM service facility that has experience with the C7 as many of the smaller ones do not.
P.S. I would do that for you except I do not own a device to ( no cell phone,old and retired) to record my car for you. If you really are stuck my wife has an i-pad that i could record my car for you and then try to figure out how to post or e-mail that to .......good luck and let us know.
Doug.
It's a fairly small dealer, but they have a "Corvette" tech.
If your dealer has a 2016 ask your sales representative to test drive it and then check the tach and see if it is oscillating. This is not normal but if you can't feel the transmission shudder I would just wait until you start feeling the shudder in the steering wheel. As I have posted, my first dealer said nothing was wrong with my transmission and the second dealer ordered a new torque converter.
My dealer says they can find nothing wrong with the car and the oscillating tach is normal. I don't think it is, but don't know where to go at this point. They still have it and he read me a GM bulletin about the condition and GM says the oscillation tach and slight vibration are normal conditions in V4 mode..
Sounds like it's time to install the Range Active Fuel Management Disable Device.
I don't want to mask a transmission issue with something like that. It'd be kind of foolish not to let it fail while under warranty no?
That too is a good thought and raises another point.....
You know you are getting RPM fluctuations on the highway in V4 mode under steady state driving. When the rpm is doing this have you tried moving the shift selector from Drive to Manual which will force the AFM into V8 MODE and then observed the RPM under those steady state driving conditions ??
Just a comment. I had the tranny replaced with 100 miles on the clock. The tech that did it was one of the best, if not the best in Central Florida. I could not tell it was done afterwards. Took him about two days, and I don't know how many helpers he had. It can be done properly. But it is a scary ordeal. Guess you need to find a dealer and specific tech that has the experience. I am sure there are far more that would butcher it given some of the incidents I have seen on this forum.
Just a comment. I had the tranny replaced with 100 miles on the clock. The tech that did it was one of the best, if not the best in Central Florida. I could not tell it was done afterwards. Took him about two days, and I don't know how many helpers he had. It can be done properly. But it is a scary ordeal. Guess you need to find a dealer and specific tech that has the experience. I am sure there are far more that would butcher it given some of the incidents I have seen on this forum.
That too is a good thought and raises another point.....
You know you are getting RPM fluctuations on the highway in V4 mode under steady state driving. When the rpm is doing this have you tried moving the shift selector from Drive to Manual which will force the AFM into V8 MODE and then observed the RPM under those steady state driving conditions ??
Yes, in V8 mode there is no fluctuation in the tach.
Just a comment. I had the tranny replaced with 100 miles on the clock. The tech that did it was one of the best, if not the best in Central Florida. I could not tell it was done afterwards. Took him about two days, and I don't know how many helpers he had. It can be done properly. But it is a scary ordeal. Guess you need to find a dealer and specific tech that has the experience. I am sure there are far more that would butcher it given some of the incidents I have seen on this forum.
Luckily magic isnt involved and replacing the trans has pretty much been the same PITA as it has been since the C5. I replaced transmissions and torque converters in my C5s and C6s in my garage with a quick lift. Cant imagine the C7 being much harder except having to remove the rear facia to get the exhaust off so you could do some body damage I guess.
There are good and bad techs/dealers. Always go into the regional forums here or find a local Corvette club and ask where the 'good' ones are.
My new-to-me 2015 Z51 A8 was delivered to me with 6400 miles on the clock on January 3, 2016.
Since then I've driven it about a thousand miles. The car seems to shift crisply with no shudders, vibrations or other anomalies that I have been able to notice.
After reading these unfortunate stories about tranny failure, I am glad I purchased an extended warranty.
Before you had you torque converter replaced did you also have the harsh 1-2 shift first drive of the day ?
When was your car built ?
TKS
Torque converter in and will be installed next week. I have never had the harsh 1-2 shift, transmission has always shifted very smooth. My car was built October, 2014, so I have one of the first A8s.
