A8 Issues
Melting Slicks
Joined: Jan 2015
Posts: 2,270
Likes: 652
From: Darien, IL
St. Jude Donor '15-'16
Melting Slicks
Joined: Apr 2015
Posts: 2,353
Likes: 779
The revised transmission is already being installed since October of last year....you are fine, don't be concerned.
Honestly, I'm not and I have the unrevised version. The issue is not an epidemic, just a possibility and I dare say a uncommon one.
Instructor
Joined: Sep 2015
Posts: 162
Likes: 60
From: Melbourne Beach, Florida
10/15 for me as well. Would suck to have just missed the new tranny by a week. There must be a way to confirm if our cars have the old or new tranny. Although, I have my doubts if this (new tranny) is fact or forum chatter.
Melting Slicks
Joined: May 2001
Posts: 2,596
Likes: 120
From: East Tennessee
Plus sometimes because something is 'changed' it doesnt necessarily mean its a good thing, they may have replaced some expensive magnesium parts with aluminum or sourced some different internal parts from China.
They made 23,232 A8 Corvettes in 2015 alone, I'm sure many of those are just fine.
IMO the OP has two problems, a transmission issue and a dealer issue. Both should probably be replaced if its that bad..
Last edited by kp; Jan 21, 2016 at 12:34 AM.
Le Mans Master
Joined: Aug 2015
Posts: 8,243
Likes: 4,615
From: Southwest Florida
I may at some point call my dealer to see if they know anything about an "updated" transmission. They are a good bunch of people and very knowledge.
Melting Slicks
Joined: Apr 2015
Posts: 2,353
Likes: 779
There is no reason he would not answer the question directly, and I don't see how a revision already in production would be proprietary information.
I, personally, would like to know the exact changes. Like that other guy posted, we don't know what exactly changed and this whole revision could be a moot point.
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Instructor
Joined: Sep 2015
Posts: 162
Likes: 60
From: Melbourne Beach, Florida
Gets my vote. Seems about as much of a discussed and controversial topic as any. Although, I don't see the answer containing a statement to the effect, "the transmission was updated to correct a known problem..." Too much liability and exposure acknowledging a known defect. Just look at Tadge's catch can answer... and then the '16 Camaro comes with a catch can.
Instructor
Joined: Jun 2015
Posts: 176
Likes: 13
From: PA
How bad is the shudder . Something noticeble like you just hit a big pot hole or just a little shake now and then which would be normal . I have the A8 and the only thing i am annoyed by is the wheel hop when turning at slow speeds. The torque converter has a rubber disk which is a flex disk . These develop cracks hard to see and they can cause issues that will effect driveability . They usually last longer then 12k depending on how you drive or where you drive as in weather . Cold can crack anything that heats up very quickly. 
Safety Car
Joined: Sep 2001
Posts: 4,495
Likes: 1,263
From: Jacksonville FL
Drifting
Joined: Nov 2014
Posts: 1,782
Likes: 106
From: Salado TX
I think I may be experience this issue too. The last time I drove down the highway at a steady speed I felt the shudder. The car was going into and out V4 mode so I thought that may have been it although the shudder was harsher than what I normally feel when it goes between V4 and V8. The car is a 2015 with a little over 9000 miles on it. I'll pay more attention next time I drive it.
Safety Car
Joined: Sep 2001
Posts: 4,495
Likes: 1,263
From: Jacksonville FL
I think I may be experience this issue too. The last time I drove down the highway at a steady speed I felt the shudder. The car was going into and out V4 mode so I thought that may have been it although the shudder was harsher than what I normally feel when it goes between V4 and V8. The car is a 2015 with a little over 9000 miles on it. I'll pay more attention next time I drive it.
Drifting
Joined: Oct 2002
Posts: 1,335
Likes: 76
From: Bedford Va.
I have an early 2016 A8 no issue.
But as far confirming an issue trans or AFM
If you feel a shutter put the car/transmission in manual at a steady highway speed.
No V4 will activate-is there shutter now?
If not it's not a trans issue.
But as far confirming an issue trans or AFM
If you feel a shutter put the car/transmission in manual at a steady highway speed.
No V4 will activate-is there shutter now?
If not it's not a trans issue.
Drifting
Joined: Jan 2012
Posts: 1,332
Likes: 557
From: Newport OR
I feel very badly for those who are going through tranny replacement issues and dealer issues as well.
I equate this to the controversial BMW motorcycle threads about failed final drives. If you read the forums, your motorcycle's final drive will fail, because it is an endemic issue that BMW cannot/will not solve, or admit exists...
Yet I wonder how many final drives really do fail? I started riding in 1999. Since then I've ridden nearly 300K (86K on one bike since 2011) Yes, we love to ride.
And yet I've never had a problem, nor has anyone else in my riding community. In fact, I checked with a large BMW shop in So Cal who told me they've replace two final drives in the past five years, and sold thousands of bikes...
My point is, the bridge that falls makes more noise than the one that stands. Be aware a problem could exist, but MANY thousands of 2015 Corvettes are just fine and will continue to run well. The internet magnifies every problem.
Good luck and do more driving with less worrying about what will probably never happen.
I equate this to the controversial BMW motorcycle threads about failed final drives. If you read the forums, your motorcycle's final drive will fail, because it is an endemic issue that BMW cannot/will not solve, or admit exists...
Yet I wonder how many final drives really do fail? I started riding in 1999. Since then I've ridden nearly 300K (86K on one bike since 2011) Yes, we love to ride.
And yet I've never had a problem, nor has anyone else in my riding community. In fact, I checked with a large BMW shop in So Cal who told me they've replace two final drives in the past five years, and sold thousands of bikes...My point is, the bridge that falls makes more noise than the one that stands. Be aware a problem could exist, but MANY thousands of 2015 Corvettes are just fine and will continue to run well. The internet magnifies every problem.
Good luck and do more driving with less worrying about what will probably never happen.
Melting Slicks
Joined: May 2001
Posts: 2,596
Likes: 120
From: East Tennessee
Gets my vote. Seems about as much of a discussed and controversial topic as any. Although, I don't see the answer containing a statement to the effect, "the transmission was updated to correct a known problem..." Too much liability and exposure acknowledging a known defect. Just look at Tadge's catch can answer... and then the '16 Camaro comes with a catch can.
The A8 trucks are having some similar issues, all seem to go back to the torque converter. Seems they wont replace the converter without replacing the trans..
I have driven a '15 and two '16s on the highway, they all had what felt like running over a bump or a rough shift when the converter locks/unlocks. I havent felt one shudder but its possible if the TCC is not right it can shudder when locking/unlocking. Especially in V4.
I'm not defending GM, too many people complaining for it to be made up. Time will tell when these cars start getting more miles on them.
Le Mans Master
Joined: Aug 2015
Posts: 8,243
Likes: 4,615
From: Southwest Florida
I recently watched a you tube video produced by MotoManTV it was a behind the screens design of the C7. Most of video was a discussion with Tadge about the C7 design elements. In one segment, Tadge discussed the reason why they decided to go with a steel torque tube instead of an aluminum TT.
Tadge stated a steel torque tube was required because of the vibration produced when the C7 switches from 8 cylinder mode to four cylinder mode and visa versa.
IMO, even with a steel torque the transition from 8 to 4 mode can still result in severe vibration in some C7s. This is why I installed an AFM disabler.
Tadge stated a steel torque tube was required because of the vibration produced when the C7 switches from 8 cylinder mode to four cylinder mode and visa versa.
IMO, even with a steel torque the transition from 8 to 4 mode can still result in severe vibration in some C7s. This is why I installed an AFM disabler.
Melting Slicks
Joined: May 2012
Posts: 2,903
Likes: 315
From: Cedar Falls Iowa
I'd be shocked if this was addressed in Ask Tadge. Didn't read the catch can response but I'm sure it was bull$h|t. That dude gets paid a lot of money to lie. I guess I'd lie to thousands too if I could make that kinda bank.
Last edited by DAFFYDRUNK; Jan 21, 2016 at 01:07 PM.
Melting Slicks
Joined: May 2001
Posts: 2,596
Likes: 120
From: East Tennessee
I recently watched a you tube video produced by MotoManTV it was a behind the screens design of the C7. Most of video was a discussion with Tadge about the C7 design elements. In one segment, Tadge discussed the reason why they decided to go with a steel torque tube instead of an aluminum TT.
Tadge stated a steel torque tube was required because of the vibration produced when the C7 switches from 8 cylinder mode to four cylinder mode and visa versa.
IMO, even with a steel torque the transition from 8 to 4 mode can still result in severe vibration in some C7s. This is why I installed an AFM disabler.
Tadge stated a steel torque tube was required because of the vibration produced when the C7 switches from 8 cylinder mode to four cylinder mode and visa versa.
IMO, even with a steel torque the transition from 8 to 4 mode can still result in severe vibration in some C7s. This is why I installed an AFM disabler.
Thats why the M7 cars dont go into V4 unless you put it in ECO, they dont have the dampening effect of a fluid filled torque converter. The torque converter clutch in these is used a lot, for both mileage, efficiency and to probably help manage trans temps. Doesnt take much, whether mechanical or bad programming, to mess things up and feel it.
The whole trans was new in 2015, I was a little surprised that people who not buy a 'first year' 2014 Corvette lined up to buy a 'first year' auto transmission - one of the most complex mechanical parts of the car. My wife's Jeep has gone through two 'new' 9 speed autos in under 10,000 miles, and hers is far from the only one. Yet the new Cherokee is still one of the strongest sellers for Jeep - go figure.
But then again the 'classic' A6 in my '15 Silverado is the worst shifting auto trans I have ever owned. The A6 in my old '14 was far from perfect as well but it didnt have the occasional jolts and the busyness of the A8.
Melting Slicks
Joined: Apr 2015
Posts: 2,353
Likes: 779
I recently watched a you tube video produced by MotoManTV it was a behind the screens design of the C7. Most of video was a discussion with Tadge about the C7 design elements. In one segment, Tadge discussed the reason why they decided to go with a steel torque tube instead of an aluminum TT.
Tadge stated a steel torque tube was required because of the vibration produced when the C7 switches from 8 cylinder mode to four cylinder mode and visa versa.
IMO, even with a steel torque the transition from 8 to 4 mode can still result in severe vibration in some C7s. This is why I installed an AFM disabler.
Tadge stated a steel torque tube was required because of the vibration produced when the C7 switches from 8 cylinder mode to four cylinder mode and visa versa.
IMO, even with a steel torque the transition from 8 to 4 mode can still result in severe vibration in some C7s. This is why I installed an AFM disabler.
I'm no expert and still learning, myself, but i believe the TC slip is computer controlled to "micro" slip when the AFM transition is made in order to absorb some of the vibrations. A DCT is not able to do this, thus the requirement for a classic torque converter auto.
This is a great transmission, all issues aside. It shifts in auto faster than a dual clutch, even though technically speaking there are alot of similarities between a DCT and this 8L90 that it shifting as fast, or faster, shouldn't be a surprise to anyone.