Four considerations/questions:

First, the GMPP extended warranty offered by Ken Fichner at a discount is again on my mind for serious consideration since my build was early 2015.

Second, is the problem only happening on some or can everyone with this tranny expect to see the issue in the usual life of their car?

Third, what percent has precipitated a recall vs a service advisory when the issue arises?

Fourth, is the cost of this specific, potential recall beyond what GM has stepped up on in previous issues?

Inquiring minds want to know......

 

Someone Please ask.....

 

All the more reason to buy an extended warranty before our factory warranty expires. I believe an extended warranty is no longer optional but mandatory.

 

bit the bullet and bought a 7 yr GMEPP. I won't keep the car longer than 7 years.

 

this pile of junk most likely will be long gone and out of my life before my three year warranty is up ....
even if they recall the tranny ..who the hell wants to have their car torn apart ..... unreal !!!

 

"who the hell wants to have their car torn apart"

that would be a nightmare scenario...to get the C7 tranny out they really have to remove just about everything underneath from the tranny forward.

 

I took it out on a smooth, flat, road (I really had to look for one around here!) and put the cruise on at 65. When it's in Drive, it goes into v4 mode and there is a shudder I can feel in the seats every time the RPM goes up and down. Put it in M, and it stays in V8 mode and doesn't shudder and the RPM remain steady.

I took it into the dealer and they are checking it out this morning.

 

Keep us updated on what they diagnose.

 

FWIW I tried mine yesterday, fairly flat road, 65mph with the cruise on. I was logging some basic parameters with HP tuner and from what I can see when the car goes into V4, the torque converter unlocks (rpm goes up) when the car goes back to V8 the torque converter locks and the RPM drops. It didnt do it in any kind of pattern or rhythm, when the car needed to accelerate it dropped out of V4 and the rpm would change. Mine doesnt shudder or vibrate when the V4/V8 switches or the converter locks/unlocks/rpm changes with 2000 miles on it. When it was new you could feel the converter lock/unlock on the highway, but it was more like running over a bump or a gear change, that went away in a few hundred miles.

Mine may start acting up down the road, its a July '15 2016, have to wait and see..

 

my soon to be head ache ..was built a month later for times are a com'in..

 

Here's a video of my tach when its doing it. It never leaves V4 mode so its not the AFM working.

 

That is just the cruise control trying to maintain speed with only 4 cylinders to work with. Mine does the same thing. It is only varying about 50 to 75 rpms.

Reb

 

I don't think so. I never noticed it before and it certainly wasn't accompanied by a vibration you can feel in the seat and wheel every time it happens.

 

Maybe, maybe not. There are 23,000 '15 A8 cars running around. The majority are OK I would imagine or they just dont notice a problem. Enjoy the car until it has problems, it may never have an issue..

 

I haven't seen the oscillating tach syndrome that Earnest T observes, but to double-check I took a test ride this afternoon. I see no such RPM variance while at highway speeds with cruise control enabled in V4 mode. The V4-V8 transition has always been imperceptible most of the time, mostly only felt in highway use on hills. I also have not noticed the torque converter locking or unlocking, and there certainly have never been any vibrations or other unusual sensations described by some here. Next week will mark one year of ownership, making my C7 A8 one of the earliest A8 examples (build date 12/18/14) reporting here and in several other threads on A8 issues, quirks, and complaints.

Some of this will be repetitive from previous threads, but here are my observations of A8 behavior to date. In the first month of ownership I noticed two instances of hard downshifting from 2-1 or perhaps 3-1, but that disappeared, presumably from adaptive learning. Last November I had the dealer update the TCM software followed by the "fast learn" procedure to address two other minor issues I was having. Before the update I always noticed a slight flare on the first cold 1-2 shift after exiting the garage, but after the software update that shift has become much more crisp, as have all other shifts hot or cold. I never had any hard upshifts as reported by many A8 owners.

That's the good news, but there really isn't any bad news--only one bit of what you might call "weird news." In early May, three months after taking ownership, the car failed to engage reverse immediately one morning after a cold start. The "R" on the DIC blinked during the delay but reverse engaged properly after I shifted to drive, then back to reverse. This behavior recurred two more times in the next three days, always when cold. Almost exactly three months later in July it happened again but only once this time. Three months later in October it happened twice, then again one time in early January. If I don't shift to drive and back to reverse there will be a delay of about 5-6 sec., always accompanied by the blinking "R" on the DIC. Between these events everything works normally, but the almost clockwork schedule of occurrence, 1-3 instances every three months, makes it all the more baffling.

The service manager at a nearby dealer who sells lots of Corvettes is also baffled and has no answers, but thought the software update in November might fix it. It didn't, but after reading this and other threads I'm inclined to think the delay may be the torque converter drain-down described by Black&White and others. If so, what's with this three-month schedule it keeps? Frankly, if it remains as innocuous as it is now I will not complain, as the A8 otherwise works flawlessly. I would like to know what's causing it, though. Someone, somewhere in the labyrinth of GM engineering knows what the blinking "R" means, but to date I've gotten no answers. The car has never thrown a trouble code of any kind.

I do worry about the o-ring and other problems reported by a few here, but I can't help from thinking that most A8s are working quite well without issues and that most will remain trouble-free for the duration. I hope I'm not being overly optimistic.

 

About a month before the NCM bash I will post a thread for all having A8 issues to email me a letter with vin numbers and concerns and repair order copies. I will most certainly pose the question to Tadge and hand him the letters and repair orders.

 

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..

 

RE post 94. Like iclick I have an early built 2015 A8, second week of production that in Drive after first harsh 1-2 shift of the day shifts smoothly during normal day to day driving. However as I have previously posted, with spirited acceleration the shifts are very harsh and in Manual using the paddles while accelerating through 3rd gear there is a very hard "clunk" in the drive train. This clunk happens with easy acceleration as well as harder acceleration.
So far I have not taken the car in for repairs as our service manager has no idea what the problem is and I don't think GM has a fix. Shortly after my car was built GM issued service bulletin GM 14-07-30-001A to deal with Harsh Shifts. This was then superseded by version -001B then -001C. Some owners here report their A8 is fixed while others have reported the problems have returned or were not fixed except by transmission/torque converter replacement.
I am convinced there is a problem with my A8 that will eventually lead to its failure. I fully intend to take it in for repairs prior to being out of warranty. The fix may require a transmission/torque converter replacement but at this point I don't think there is a satisfactory fix available. I am hoping GM will come up with a fix that does not require tearing the transmission out of the car........so I am waiting.
I have seen posts that suggest the A8 issues are small in numbers. Here in Florida I have met two new A8 owners and they too have a harsh 1-2 shift first drive of the day.They are older guys (like me) and are not aware of our forum. This leads me to believe there are many C7 A8 owners out there that have the same issues we do but we don't hear from them.

I think Black and White has a great idea of presenting the A8 issues and concerns to GM at the NCM bash this spring............
just my $.02

 

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.

 

Replacing A8 without a warranty would be $$$$$$$.