A8 Transmission failure tracking
10-31-2018, 10:25 AM
#802
Le Mans Master
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St. Jude Donor '15-'16,'18
Torque converter was replaced at 12K miles. Tranny flushed and new tranny filter at 18K miles. Using Range now. No shudder. Fingers crossed.
10-31-2018, 02:27 PM
#803
Racer
I do have to say since my flush and re-fill, the transmission has a different and much better personality during all shifting conditions.
It's a functional issue.
It's like you are driving on a washboard when going down a perfectly smooth road.
If you've ever driven on a gravel road that was recently subjected to heavy rains days previous, it's like that.
All that slipping and grabbing inside the transmission can not be good for the entire driveline.
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VaydorVette1 (11-01-2018)
11-01-2018, 08:00 AM
#804
Racer
Maybe a dumb question but if you shifted to neutral and coasted would the shutter or feeling of being on a washboard stop? I’m starting to think I’m getting this washboard feel but our roads are so crappy hard to tell for sure.
Last edited by plake; 11-01-2018 at 08:52 AM. Reason: spelling
11-01-2018, 08:22 AM
#805
You have hit on a key problem because of the problems with shudder from the lockup clutch are so common that ANY vibration of this type in a C7 (or other 8L45/8L90 equipped GM vehicle) will be instantly diagnosed as a torque converter issue even though there are numerous other engine and drivetrain faults that will closely mimic this problem. This is the reason why GM has very clear instructions in the diagnosis/repair TSB for operating the converter clutch in its fully locked and unlocked modes (where shutter from the converter clutch won't occur) to ensure that the issue really is the converter.
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VaydorVette1 (11-01-2018)
11-01-2018, 09:24 AM
#806
2nd Gear
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Are there any C7 A8 with higher milage and without A8 problems? Or will every A8 sooner or later have problems?
Thanks.
Thanks.
Last edited by Francis GR; 11-01-2018 at 09:25 AM.
11-01-2018, 09:33 AM
#807
My 2 cents:
1. A lot of C7 A8s are not driven enough to notice the problem(s).
2. Some drivers don't know if what they feel is a potential issue. I have a couple folks in our club heard me talking about the issues I have had and said " I thought I was feeling something" corvettes and GM trucks with A8 both.
3. Some A8s may not have the problem but my guess is most A8s from 2015 - 2017 and early 2018s have the same issue at different levels..
1. A lot of C7 A8s are not driven enough to notice the problem(s).
2. Some drivers don't know if what they feel is a potential issue. I have a couple folks in our club heard me talking about the issues I have had and said " I thought I was feeling something" corvettes and GM trucks with A8 both.
3. Some A8s may not have the problem but my guess is most A8s from 2015 - 2017 and early 2018s have the same issue at different levels..
11-01-2018, 11:47 AM
#811
It is Doc ID: 4526930
#16-NA-175: Shake and /or Shudder During Light Throttle Acceleration Between 25 and 80 MPH (40 and 128 KM/H) at a Steady State - (Oct 11,2018) which says "Do not replace TC or transmission. A revised service procedure will be released in Ist Q1 of 2019. It shows Corvette 2015 tru 2019 models.
Heidi
Save the Wave
#16-NA-175: Shake and /or Shudder During Light Throttle Acceleration Between 25 and 80 MPH (40 and 128 KM/H) at a Steady State - (Oct 11,2018) which says "Do not replace TC or transmission. A revised service procedure will be released in Ist Q1 of 2019. It shows Corvette 2015 tru 2019 models.
Heidi
Save the Wave
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VaydorVette1 (11-02-2018)
11-01-2018, 09:24 PM
#812
My 2 cents:
1. A lot of C7 A8s are not driven enough to notice the problem(s).
2. Some drivers don't know if what they feel is a potential issue. I have a couple folks in our club heard me talking about the issues I have had and said " I thought I was feeling something" corvettes and GM trucks with A8 both.
3. Some A8s may not have the problem but my guess is most A8s from 2015 - 2017 and early 2018s have the same issue at different levels..
1. A lot of C7 A8s are not driven enough to notice the problem(s).
2. Some drivers don't know if what they feel is a potential issue. I have a couple folks in our club heard me talking about the issues I have had and said " I thought I was feeling something" corvettes and GM trucks with A8 both.
3. Some A8s may not have the problem but my guess is most A8s from 2015 - 2017 and early 2018s have the same issue at different levels..
I track mine extensively, with some highway driving. I haven't experienced this shuttering and would like more details. <> Is the shuttering for a short duration or does it hold on for an extended period? Is the TSB only a software flash? I've read where tranny fluid has been changed and that seemed to resolve it. With a little over 10K miles half are hard miles when does this problem rear it's head? Could the problem be created by babying the car too much and driving way to easy? Driving it easy the trans will learn your driving habits.
Last edited by Hershey71; 11-01-2018 at 09:28 PM.
11-01-2018, 09:25 PM
#813
Intermediate
Just updated with mine.
I am a little worried though because I just bought the car it has 33,xxx miles on it. I just wonder how long it was going on, and if prolonged shuddering has damaged the TC. Does anyone have any experience with a shudder that has been going on so long it damaged the TC?
The car is at the dealer now getting the triple flush done, so hopefully that fixes it. I am not super confident that it will though.
I am a little worried though because I just bought the car it has 33,xxx miles on it. I just wonder how long it was going on, and if prolonged shuddering has damaged the TC. Does anyone have any experience with a shudder that has been going on so long it damaged the TC?
The car is at the dealer now getting the triple flush done, so hopefully that fixes it. I am not super confident that it will though.
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VaydorVette1 (11-02-2018)
11-02-2018, 07:40 AM
#814
Instructor
Mine shudders for about 5-6 sec every 1-2 min at speeds greater than 40mph. Absolutely annoying. SO....I order the Range Tech module in hopes that it would give some relief. To my surprise (because I'm a skeptic), it actually took the shudder away. I hope this is the fix and it lasts.
11-03-2018, 07:24 AM
#815
Burning Brakes
I have a 2016 Z51 with 5,200 miles built 10-2015 and it had the shudder problem. Dealer claimed flushing the fluid with Mobil 1 tranny fluid solves the problem in 99% of them so I let them flush the fluid. After driving for about 50 miles the problem seems to be gone, I will keep my fingers crossed and update you if the problem returns.
John
John
I have put about 300 miles on the car and I took it for a ride yesterday and the problem has returned. No as bad as it was but it has returned. The problem does go away if I put it in manual shifting mode so I know that the AFM is the problem. Just to clarify, the car has the 8 speed auto transmission in it with a build date of 10-2015.
I have attached the latest bulletin from GM, it is dated 10/11/2018. Half way down the first page it states they will release a new procedure in 1st quarter of 2019 and do NOT replace any parts at this time or the dealer may be charged for them. It does seem to say that a second flush might be needed, I will see what my dealer says.
Last edited by MA ZO6; 11-03-2018 at 07:39 AM.
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11-05-2018, 07:12 PM
#816
Racer
Drove my 2016 Stingray today trying to figure out if I have any issues. 7800 miles and I must confirm it feels like I’m on a washboard a lot of the time. Subtle at times but it’s there. Dam, I wanted the M7 but wife overruled. I am even running the Range device. I hope GM has this fix coming out after the first of the year. I love this car and bought it at the right price with 5000 miles, now this crap.
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VaydorVette1 (11-06-2018)
11-10-2018, 12:09 PM
#817
Heel & Toe
Member Since: Oct 2018
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I have put about 300 miles on the car and I took it for a ride yesterday and the problem has returned. No as bad as it was but it has returned. The problem does go away if I put it in manual shifting mode so I know that the AFM is the problem. Just to clarify, the car has the 8 speed auto transmission in it with a build date of 10-2015.
I have attached the latest bulletin from GM, it is dated 10/11/2018. Half way down the first page it states they will release a new procedure in 1st quarter of 2019 and do NOT replace any parts at this time or the dealer may be charged for them. It does seem to say that a second flush might be needed, I will see what my dealer says.
I have attached the latest bulletin from GM, it is dated 10/11/2018. Half way down the first page it states they will release a new procedure in 1st quarter of 2019 and do NOT replace any parts at this time or the dealer may be charged for them. It does seem to say that a second flush might be needed, I will see what my dealer says.
11-12-2018, 01:29 PM
#818
23000 miles. Oscillations are back up to 100rpms with mild to moderate shudder in pulses. I'm contemplating another flush or waiting until next year pending this supposed update.
11-14-2018, 11:08 AM
#819
Still Buying
After reading all the A8 issues, I could never see purchasing a car with one. Curious how folks make peace with this issue and buy anyway. Those that are informed of course.
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VaydorVette1 (11-15-2018)
11-14-2018, 11:15 AM
#820
Le Mans Master
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