Notices
C7 Z06 Discussion General Z06 Corvette Discussion, LT4 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Sponsored by:
Sponsored by:

A8 tuning to fix shudder

 
Old 01-16-2019, 09:17 PM
  #1  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default A8 tuning to fix shudder

Hey guys, can anyone tell me, specifically, what needs to be addressed in the tune to fix the dreaded shudder issue on the A8? Mine is a 2015, and I know tuning is available. I would like to be able to share with my tuner so we aren't randomly adjusting things. I do realize that tuning is an art, but I'm hoping that someone can share a few 'secrets' to help the entire C7Z family. It sounds like the 2019 "fix" is just another fluid change? They have a new synthetic fluid that will be released in February, I guess? Not convinced that this is going to fix the shudder. I've already had the latest fluid change and it's still there.
1QUICK Z is offline  
Old 01-16-2019, 09:33 PM
  #2  
Higgs Boson
CF Senior Member
 
Higgs Boson's Avatar
 
Member Since: Jul 2007
Location: Texas Hill Country
Posts: 9,527
Thanked 964 Times in 627 Posts
Default

gm tries to keep the converter locked way too much and it's not robust enough to handle it. unlock the converter except during cruise in higher gears and when you do lock it, make sure it's locked down tight.

also, I didn't include it since it is a given, but also turn off AFM.

Last edited by Higgs Boson; 01-17-2019 at 07:45 AM.
Higgs Boson is offline  
Old 01-16-2019, 09:36 PM
  #3  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default

Thanks Higgs
1QUICK Z is offline  
Old 01-17-2019, 09:47 AM
  #4  
azcanuk
CF Senior Member
 
azcanuk's Avatar
 
Member Since: Jan 2008
Location: Mesa AZ
Posts: 1,442
Thanked 98 Times in 82 Posts
Default

Originally Posted by Higgs Boson View Post
also, I didn't include it since it is a given, but also turn off AFM.
Turn it off? In the A8 thought the only way to "turn it off" was to use Manual mode or install a Range AFM disabler?

azcanuk is offline  
Old 01-17-2019, 11:29 AM
  #5  
tzoid9
CF Senior Member
 
tzoid9's Avatar
 
Member Since: Jan 2016
Posts: 949
Thanked 164 Times in 132 Posts
Default

Originally Posted by azcanuk View Post
Turn it off? In the A8 thought the only way to "turn it off" was to use Manual mode or install a Range AFM disabler?
I am no authority on this subject (Higgs is), but the tuner I spoke with told me it is a fairly simple adjustment while making an engine tune that can eliminate the cylinder deactivation. My personal concern on this subject is if my new car experiences any kind of drive train warrantable problem in the early stage of ownership (say under 5000 miles), I want to be sure I have it covered under the GM warranty. A tune would very likely eliminate that coverage.
tzoid9 is offline  
Old 01-17-2019, 06:02 PM
  #6  
tertiumquid
CF Senior Member
 
tertiumquid's Avatar
 
Member Since: Jun 2015
Location: Cumming, GA
Posts: 327
Thanked 130 Times in 81 Posts
Default

Originally Posted by tzoid9 View Post
I am no authority on this subject (Higgs is), but the tuner I spoke with told me it is a fairly simple adjustment while making an engine tune that can eliminate the cylinder deactivation. My personal concern on this subject is if my new car experiences any kind of drive train warrantable problem in the early stage of ownership (say under 5000 miles), I want to be sure I have it covered under the GM warranty. A tune would very likely eliminate that coverage.
You can stay away from any potential tune complications by simply plugging in a Range module. That will kill the AFM as long as it's in and will never affect the rest of the vehicle operation and will not cause a problem with any warranty situation. All you need to do when taking it to a dealer for work is to unplug it. There's no traceable record of it in the ECM.
tertiumquid is offline  
Old 01-17-2019, 06:42 PM
  #7  
Higgs Boson
CF Senior Member
 
Higgs Boson's Avatar
 
Member Since: Jul 2007
Location: Texas Hill Country
Posts: 9,527
Thanked 964 Times in 627 Posts
Default

Originally Posted by azcanuk View Post
Turn it off? In the A8 thought the only way to "turn it off" was to use Manual mode or install a Range AFM disabler?
op is talking about tuning.
Higgs Boson is offline  
Old 01-17-2019, 08:00 PM
  #8  
tzoid9
CF Senior Member
 
tzoid9's Avatar
 
Member Since: Jan 2016
Posts: 949
Thanked 164 Times in 132 Posts
Default

Originally Posted by tertiumquid View Post
You can stay away from any potential tune complications by simply plugging in a Range module. That will kill the AFM as long as it's in and will never affect the rest of the vehicle operation and will not cause a problem with any warranty situation. All you need to do when taking it to a dealer for work is to unplug it. There's no traceable record of it in the ECM.
Another thread regarding A8 issues, had all kinds info and feedback on the Range Technology disabler device. I have two issues with the new A8 Z06 I bought.....low end bog and the cylinder deactivation. Both can be fixed quite easily with a tune....but, you risk a bundle if you have a powertrain failure under warranty. And with all the articles that have been posted on A8 early hour failures, I'm too chicken to risk that issue by fixing my two issues the right way... a conservative tune. The A8 crapping out for no reason associated with my minimal tune, and GM will stick it up my kiester in a heart beat. So the Range device solves one of them (which I already bought) and it appears the Mamo throttle body + BMS filter combination, does decently on the other. I still prefer the tune idea, just can't risk it!
tzoid9 is offline  
Old 01-17-2019, 08:35 PM
  #9  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default

Guys, this thread was started to discuss A8 tuning and fixing the shudder issue. Can we please stay on topic. There are plenty of threads on AFM. I would like to learn about the shudder issue and who has been able to fix it with tuning. Thanks!
1QUICK Z is offline  
Old 01-17-2019, 09:02 PM
  #10  
pkincy
CF Senior Member
 
pkincy's Avatar
 
Member Since: Jun 2003
Location: San Diego Ca
Posts: 3,898
Thanked 461 Times in 359 Posts
Default

Well the AFM gets a lot of blame for contributing to shudder, but remember that the shudder problem is across all the GM A8s and many of them do not have AFM.
pkincy is offline  
Old 01-17-2019, 09:13 PM
  #11  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default

Originally Posted by pkincy
Well the AFM gets a lot of blame for contributing to shudder, but remember that the shudder problem is across all the GM A8s and many of them do not have AFM.
Yeah, that's a good point, but this thread is turning into only discussing AFM. My shudder has nothing to do with AFM. That was turned off on my engine custom tune
1QUICK Z is offline  
Old 01-17-2019, 09:46 PM
  #12  
Higgs Boson
CF Senior Member
 
Higgs Boson's Avatar
 
Member Since: Jul 2007
Location: Texas Hill Country
Posts: 9,527
Thanked 964 Times in 627 Posts
Default

i have not found afm and TC issue to be related, AFM active can feel very juddery but it is not the same issue so I can see people thinking disabling AFM cures TC shudder.

my 2015 6.2 silverado (that I got rid of at 5000 miles due to A8 issues) had disabled AFM in the tune and felt like I was driving off road, lol. no thanks.
Higgs Boson is offline  
Old 01-17-2019, 09:58 PM
  #13  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default

Thankfully mine isn't terrible but once you know it's there, it is annoying.
1QUICK Z is offline  
Old 01-17-2019, 10:47 PM
  #14  
tertiumquid
CF Senior Member
 
tertiumquid's Avatar
 
Member Since: Jun 2015
Location: Cumming, GA
Posts: 327
Thanked 130 Times in 81 Posts
Default

As explained in other posts, the AFM system is highly suspect in the A8 shudder problem due to the fact that it causes the TC to clutch and declutch excessively so the problem isn't actually the tranny, it's the TC where the shudder is coming from. The original fluid is also implicated but the two taken together seem to cause the problem sometime after the 6K mileage point. Given that apparent casual linkage, I think the comments are not off-topic. OP wants to eliminate the shudder problem with a tune to eliminate the the AFM which will probably work but as another poster has pointed out, there goes your drive-train warranty. The Range module works, it's simple and won't affect the warranty. How is this off topic?
tertiumquid is offline  
Old 01-17-2019, 11:30 PM
  #15  
Higgs Boson
CF Senior Member
 
Higgs Boson's Avatar
 
Member Since: Jul 2007
Location: Texas Hill Country
Posts: 9,527
Thanked 964 Times in 627 Posts
Default

Originally Posted by tertiumquid View Post
As explained in other posts, the AFM system is highly suspect in the A8 shudder problem due to the fact that it causes the TC to clutch and declutch excessively so the problem isn't actually the tranny, it's the TC where the shudder is coming from. The original fluid is also implicated but the two taken together seem to cause the problem sometime after the 6K mileage point. Given that apparent casual linkage, I think the comments are not off-topic. OP wants to eliminate the shudder problem with a tune to eliminate the the AFM which will probably work but as another poster has pointed out, there goes your drive-train warranty. The Range module works, it's simple and won't affect the warranty. How is this off topic?
the person calling the comments off topic is the OP.

the range module may help band-aid one of the "casual links," as you state, but it is not a cure.
Higgs Boson is offline  
Old 01-18-2019, 12:04 AM
  #16  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default

Guys, I was not aware that AFM had anything to do with the shudder. Since mine has been turned off for almost a year, why am I still experiencing shudder?
1QUICK Z is offline  
Old 01-18-2019, 12:28 AM
  #17  
Mike Jesse
CF Senior Member
 
Member Since: Aug 2016
Location: Bremerton Wa.
Posts: 636
Thanked 145 Times in 125 Posts
Default

I had mine tuned at approximately 4800 miles.
First order of business is to remove the TCU from the right rear of the car and send it to HP Tuners.
They will then "unlock" it so the tune can be performed.
It takes all of 10 minutes to have it out and in your hands.
Once it comes back from HP, install and drive as before until the tune is performed.
I had NicD at Corde's perform the tune along with other mods.
First off the part throttle shifts are firmed up and the lazy feeling is all but gone.
AFM was turned off at this time as well. I assume Nic does this automatically.
Full throttle shifts happen right now and all occur at about 6400 RPM.
The car now has 8200 miles showing without any issues from the TCU tune.
Mine never exhibited the dreaded shudder and the fluid has never been changed.
My Z06 is a 17.
Would I do it again? YES!

Last edited by Mike Jesse; 01-18-2019 at 12:33 AM.
Mike Jesse is offline  
Old 01-18-2019, 07:02 AM
  #18  
tertiumquid
CF Senior Member
 
tertiumquid's Avatar
 
Member Since: Jun 2015
Location: Cumming, GA
Posts: 327
Thanked 130 Times in 81 Posts
Default

Originally Posted by 1QUICK Z View Post
Guys, I was not aware that AFM had anything to do with the shudder. Since mine has been turned off for almost a year, why am I still experiencing shudder?
Your TC was already damaged by the time you did the mod.
tertiumquid is offline  
Old 01-18-2019, 10:48 AM
  #19  
1QUICK Z
CF Senior Member
Thread Starter
 
1QUICK Z's Avatar
 
Member Since: Apr 2015
Location: Hager City WI
Posts: 1,105
Thanked 72 Times in 63 Posts
Default

Originally Posted by tertiumquid
Your TC was already damaged by the time you did the mod.
That's possible but I still think this is more of a fluid and tuning issue? Several guys have replaced their TC and the shudder eventually comes back.
1QUICK Z is offline  
Old 01-18-2019, 01:15 PM
  #20  
Kevin Parent
CF Senior Member
 
Member Since: May 2016
Posts: 162
Thanked 8 Times in 8 Posts
Default

Whats the cost to unlock and tune a 2017 C7 Z06 trans?
Kevin Parent is offline  

Thread Tools
Search this Thread
Quick Reply: A8 tuning to fix shudder


Sponsored Ads
Vendor Directory

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: