A8 Transmission failure tracking
#721
Drifting
Member Since: Jan 2015
Location: Fleming Island Florida
Posts: 1,832
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Going on day 3 without an answer back from GM tech support. Very frustrating! What’s even more maddening is I’ll bet most of these so-called “fixes” aren’t fixes at all. They’re just work-arounds. I’ve had 2 new transmissions, 2 torque converters, 2 new valve-bodies installed. The new TC took care of the AFM/V4 mode shudders long ago, but nothing has helped the harsh engagement shifting from Park to Drive after car sits with engine off for extended period. The sad reality is whatever action GM takes, they all have failed eventually. Basically that means a car with the A8 that sits undriven with low mileage, will most likely experience some sort of problem. GM doesn’t know what the long-term fix is obviously.
Quick update: Two weeks ago, my service dept. was advised by GM regional reps to do two calibrations in a particular order. They were something like "Clutch fill timing calibration" the other was "Engage timing calibration." (or something similar) - Well, I'll have to say I'm shocked, but in about 10 cold starts, my transmission no longer slams me back into the seat when shifting from Park to Drive.
#722
Heel & Toe
[QUOTE=stevettec7;1597654850]Quick update: Two weeks ago, my service dept. was advised by GM regional reps to do two calibrations in a particular order. They were something like "Clutch fill timing calibration" the other was "Engage timing calibration." (or something similar) - Well, I'll have to say I'm shocked, but in about 10 cold starts, my transmission no longer slams me back into the seat when shifting from Park to Drive.[/QUOTE
Congratulations!!! I certainly hope this works for you!!! We took our Z51 in yesterday and I am thinking this is the beginning of a long run around for us. I mentioned the two TSBs and got the stock answer that they have never seen the issue and it probably isn’t a warranty issue. Even mentioned that if they do replace the fluid (not sure yet) the labor would probably not be covered. Hubby is pretty even keeled, not like hot head me and he was darn angry that after spending $$$$$ they act like we don’t know a thing. So, we shall see, we shall see.
Congratulations!!! I certainly hope this works for you!!! We took our Z51 in yesterday and I am thinking this is the beginning of a long run around for us. I mentioned the two TSBs and got the stock answer that they have never seen the issue and it probably isn’t a warranty issue. Even mentioned that if they do replace the fluid (not sure yet) the labor would probably not be covered. Hubby is pretty even keeled, not like hot head me and he was darn angry that after spending $$$$$ they act like we don’t know a thing. So, we shall see, we shall see.
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stevettec7 (07-25-2018)
#723
Drifting
Quick update: Two weeks ago, my service dept. was advised by GM regional reps to do two calibrations in a particular order. They were something like "Clutch fill timing calibration" the other was "Engage timing calibration." (or something similar) - Well, I'll have to say I'm shocked, but in about 10 cold starts, my transmission no longer slams me back into the seat when shifting from Park to Drive.
#724
Heel & Toe
[QUOTE=C7 Sandy;1597656431]
UPDATE:: Dealer called yesterday and said he could not replicate issue. He had his tech take it out for a longer ride and he did find it shuddering. So the serv. Mgr. Said he will replace the trans fluid under the first TSB. No charge. Also mentioned that they found no other issues with their initial inspection (I would hope so with only 15,000 miles of older people driving) BUT that the tech recommended replacing the rear differential fluid as it is a maintenance item. What?? At 15,000 miles??? I said I would review our manual for recommended intervals. It is a $169 charge to replace something recommended by GM at 45,000 miles!!!! So, I am feeling since they are doing warranty work at no charge to me and probably a low payout from GM to them they want me to pay for something that is not a watrNty issue to make up for it. Have owned many many vehicles neatly 48 years of driving and never had to replace rear fluids!!! 😡
Quick update: Two weeks ago, my service dept. was advised by GM regional reps to do two calibrations in a particular order. They were something like "Clutch fill timing calibration" the other was "Engage timing calibration." (or something similar) - Well, I'll have to say I'm shocked, but in about 10 cold starts, my transmission no longer slams me back into the seat when shifting from Park to Drive.[/QUOTE
Congratulations!!! I certainly hope this works for you!!! We took our Z51 in yesterday and I am thinking this is the beginning of a long run around for us. I mentioned the two TSBs and got the stock answer that they have never seen the issue and it probably isn’t a warranty issue. Even mentioned that if they do replace the fluid (not sure yet) the labor would probably not be covered. Hubby is pretty even keeled, not like hot head me and he was darn angry that after spending $$$$$ they act like we don’t know a thing. So, we shall see, we shall see.
Congratulations!!! I certainly hope this works for you!!! We took our Z51 in yesterday and I am thinking this is the beginning of a long run around for us. I mentioned the two TSBs and got the stock answer that they have never seen the issue and it probably isn’t a warranty issue. Even mentioned that if they do replace the fluid (not sure yet) the labor would probably not be covered. Hubby is pretty even keeled, not like hot head me and he was darn angry that after spending $$$$$ they act like we don’t know a thing. So, we shall see, we shall see.
UPDATE:: Dealer called yesterday and said he could not replicate issue. He had his tech take it out for a longer ride and he did find it shuddering. So the serv. Mgr. Said he will replace the trans fluid under the first TSB. No charge. Also mentioned that they found no other issues with their initial inspection (I would hope so with only 15,000 miles of older people driving) BUT that the tech recommended replacing the rear differential fluid as it is a maintenance item. What?? At 15,000 miles??? I said I would review our manual for recommended intervals. It is a $169 charge to replace something recommended by GM at 45,000 miles!!!! So, I am feeling since they are doing warranty work at no charge to me and probably a low payout from GM to them they want me to pay for something that is not a watrNty issue to make up for it. Have owned many many vehicles neatly 48 years of driving and never had to replace rear fluids!!! 😡
#725
Sandy,
I like getting the differential fluid out early to get the wear materials out that develop during initial break-in. GM doesn't require this early change although some of their suppliers used to do so. If having a large amount of metal powder in the rear axle lubricant was a good thing the fluid would come pre-charged with waste metal particles
$169 sounds a little high but not out of bounds for a dealer. I changed mine at 1,000 miles like I do in all of my vehicles and it took around 30 minutes and cost under $30 for the correct GM limited slip modified fluid.
As to the shudder, I won't let my 2016 Z06 go into V4 mode which is at the root of the shudder issue. The new friction modified fluid works better with GM's idiotic AFM vibration reduction strategy and helps mask already existing damage to the torque converter lockup clutch but it doesn't do away with the abuse of the clutch that occurs continuously while the engine is operating in 4 cylinder mode. If you plan to keep your Corvette long term plug in a Range anti-AFM module to keep it out of V4 mode and forget the minor fuel savings that occurs in reduced cylinder operation. If you plan on keeping the car long term (out-of-warranty) then the long term costs of that V4 mode fuel savings strategy will greatly outweigh the amount you saved on fuel. If you plan to only keep it a short time then allow AFM to work and trade the car or sell it to an enemy instead of a friend.
I like getting the differential fluid out early to get the wear materials out that develop during initial break-in. GM doesn't require this early change although some of their suppliers used to do so. If having a large amount of metal powder in the rear axle lubricant was a good thing the fluid would come pre-charged with waste metal particles
$169 sounds a little high but not out of bounds for a dealer. I changed mine at 1,000 miles like I do in all of my vehicles and it took around 30 minutes and cost under $30 for the correct GM limited slip modified fluid.
As to the shudder, I won't let my 2016 Z06 go into V4 mode which is at the root of the shudder issue. The new friction modified fluid works better with GM's idiotic AFM vibration reduction strategy and helps mask already existing damage to the torque converter lockup clutch but it doesn't do away with the abuse of the clutch that occurs continuously while the engine is operating in 4 cylinder mode. If you plan to keep your Corvette long term plug in a Range anti-AFM module to keep it out of V4 mode and forget the minor fuel savings that occurs in reduced cylinder operation. If you plan on keeping the car long term (out-of-warranty) then the long term costs of that V4 mode fuel savings strategy will greatly outweigh the amount you saved on fuel. If you plan to only keep it a short time then allow AFM to work and trade the car or sell it to an enemy instead of a friend.
#726
Heel & Toe
A8 Tranny issues
Sandy,
I like getting the differential fluid out early to get the wear materials out that develop during initial break-in. GM doesn't require this early change although some of their suppliers used to do so. If having a large amount of metal powder in the rear axle lubricant was a good thing the fluid would come pre-charged with waste metal particles
$169 sounds a little high but not out of bounds for a dealer. I changed mine at 1,000 miles like I do in all of my vehicles and it took around 30 minutes and cost under $30 for the correct GM limited slip modified fluid.
As to the shudder, I won't let my 2016 Z06 go into V4 mode which is at the root of the shudder issue. The new friction modified fluid works better with GM's idiotic AFM vibration reduction strategy and helps mask already existing damage to the torque converter lockup clutch but it doesn't do away with the abuse of the clutch that occurs continuously while the engine is operating in 4 cylinder mode. If you plan to keep your Corvette long term plug in a Range anti-AFM module to keep it out of V4 mode and forget the minor fuel savings that occurs in reduced cylinder operation. If you plan on keeping the car long term (out-of-warranty) then the long term costs of that V4 mode fuel savings strategy will greatly outweigh the amount you saved on fuel. If you plan to only keep it a short time then allow AFM to work and trade the car or sell it to an enemy instead of a friend.
I like getting the differential fluid out early to get the wear materials out that develop during initial break-in. GM doesn't require this early change although some of their suppliers used to do so. If having a large amount of metal powder in the rear axle lubricant was a good thing the fluid would come pre-charged with waste metal particles
$169 sounds a little high but not out of bounds for a dealer. I changed mine at 1,000 miles like I do in all of my vehicles and it took around 30 minutes and cost under $30 for the correct GM limited slip modified fluid.
As to the shudder, I won't let my 2016 Z06 go into V4 mode which is at the root of the shudder issue. The new friction modified fluid works better with GM's idiotic AFM vibration reduction strategy and helps mask already existing damage to the torque converter lockup clutch but it doesn't do away with the abuse of the clutch that occurs continuously while the engine is operating in 4 cylinder mode. If you plan to keep your Corvette long term plug in a Range anti-AFM module to keep it out of V4 mode and forget the minor fuel savings that occurs in reduced cylinder operation. If you plan on keeping the car long term (out-of-warranty) then the long term costs of that V4 mode fuel savings strategy will greatly outweigh the amount you saved on fuel. If you plan to only keep it a short time then allow AFM to work and trade the car or sell it to an enemy instead of a friend.
Thanks for your response. We do run it around town in ECO mode most times. I like to run it in SPORT mode when I am by myself, as I prefer the handling and such. Being it’s our first Vette, we are pretty naive about a lot of stuff. I am assuming the Range module is an aftermarket item? If installing, would it not void the power train warranty and also my extended warranty? We had hoped to keep it long term and may still if it gets fixed but we shall see. Have to say, there is fear in replacing it with another C7. Manual is out of the question with my husbands really bad joints. From what I understand, these issues have to do with the A8 trans, correct? I may consider changing the diff fluid next season if we end up keeping it. Hate the thought, it is such a beautiful car!!
Thanks all all for your responses! This is why I love this forum!! Questions answered politely and lots of encouragement!!
#727
NCS5,
Thanks for your response. We do run it around town in ECO mode most times. I like to run it in SPORT mode when I am by myself, as I prefer the handling and such. Being it’s our first Vette, we are pretty naive about a lot of stuff. I am assuming the Range module is an aftermarket item? If installing, would it not void the power train warranty and also my extended warranty? We had hoped to keep it long term and may still if it gets fixed but we shall see. Have to say, there is fear in replacing it with another C7. Manual is out of the question with my husbands really bad joints. From what I understand, these issues have to do with the A8 trans, correct? I may consider changing the diff fluid next season if we end up keeping it. Hate the thought, it is such a beautiful car!!
Thanks all all for your responses! This is why I love this forum!! Questions answered politely and lots of encouragement!!
The Range module just plugs into the OBD II diagnostics port (just under the instrument panel) and it doesn't flash or reprogram the ECM. There are several parameters that have to be met before the engine can go into 4 cylinder mode and the Range module just tells the ECM these conditions haven't been met. It doesn't change any programming or leave any trace of itself. A lot of us use these in various GM vehicles and the A8 (8L90 and 8L45 transmissions with the 45 series used in lower torque platforms) have issues across the GM line when used with cylinder shut off. Basically running an engine on less than its native number of cylinders creates a lot more vibration which would be highly objectionable to the owner if it weren't heavily damped and one method of doing this is to constantly cycle the lockup clutch in the torque converter between its locked and unlocked conditions so that the fluid coupling of the unlocked torque converter is absorbing some of the vibration. Even more vibration could be absorbed and clutch damage avoided if the converter were simply left unlocked in V4 mode but the resulting loss in the "open" torque converter would pretty much offset the meager gains from V4 mode operation so this modulated clutch method was the strategy GM chose.
The engine goes into V4 mode in any driver mode with an automatic equipped Corvette but will go into V4 a little more frequently with the driver mode set to eco. The M7 only goes into V4 mode when driver mode is set to eco and European export automatic Corvettes have the same programming so they normally run in V8 mode unless the owner chooses eco mode.
The 8L90 in my 2016 Z06 has been flawless and performs very well. Although using a Range module shouldn't be necessary it is the best work-around to avoid dealing with the A8 issue and lets you enjoy the car without worrying about the transmission shudder issue returning.
Enjoy your C7!
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Layla2018 (10-05-2018)
#728
Pro
[QUOTE=C7 Sandy;1597663959]
UPDATE:: Dealer called yesterday and said he could not replicate issue. He had his tech take it out for a longer ride and he did find it shuddering. So the serv. Mgr. Said he will replace the trans fluid under the first TSB. No charge. Also mentioned that they found no other issues with their initial inspection (I would hope so with only 15,000 miles of older people driving) BUT that the tech recommended replacing the rear differential fluid as it is a maintenance item. What?? At 15,000 miles??? I said I would review our manual for recommended intervals. It is a $169 charge to replace something recommended by GM at 45,000 miles!!!! So, I am feeling since they are doing warranty work at no charge to me and probably a low payout from GM to them they want me to pay for something that is not a watrNty issue to make up for it. Have owned many many vehicles neatly 48 years of driving and never had to replace rear fluids!!! 😡
lots of owners have reported finding the differential factory fill to be missing a full quart on a three quart system.....my new 2018 was factory under filled by one quart...........maybe at least just have them check the level for you...very quick and easy to do.
UPDATE:: Dealer called yesterday and said he could not replicate issue. He had his tech take it out for a longer ride and he did find it shuddering. So the serv. Mgr. Said he will replace the trans fluid under the first TSB. No charge. Also mentioned that they found no other issues with their initial inspection (I would hope so with only 15,000 miles of older people driving) BUT that the tech recommended replacing the rear differential fluid as it is a maintenance item. What?? At 15,000 miles??? I said I would review our manual for recommended intervals. It is a $169 charge to replace something recommended by GM at 45,000 miles!!!! So, I am feeling since they are doing warranty work at no charge to me and probably a low payout from GM to them they want me to pay for something that is not a watrNty issue to make up for it. Have owned many many vehicles neatly 48 years of driving and never had to replace rear fluids!!! 😡
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NSC5 (07-25-2018)
#730
A8 Transmission
Well on 7/16 took my 2016 Corvette with 12,700 mile on to the shop and had the trans fluid drain per bulletin 16-na-175, (shuddering ) told to drive it 300 miles. No good. Took it in on 7/31 for a new torque converter, HOPE this works
#731
Instructor
Well yesterday I joined the club ! My A8 symptom free 2016 with 29600 miles and many road trips from here in Florida to way out west, up north finally gave in. Saturday it started shuttering at speed and yesterday the dealer took it in for a new torque converter. Vehicle was made in late October 2015 just after the supposed cut off date for the known bad components. Good dealership . no problems with service and ready for a road trip to Oklahoma next month!
#732
Heel & Toe
Well yesterday I joined the club ! My A8 symptom free 2016 with 29600 miles and many road trips from here in Florida to way out west, up north finally gave in. Saturday it started shuttering at speed and yesterday the dealer took it in for a new torque converter. Vehicle was made in late October 2015 just after the supposed cut off date for the known bad components. Good dealership . no problems with service and ready for a road trip to Oklahoma next month!
Awww. Sorry to hear about your issues. We are crossing our fingers the trans flushes continue to work on ours.
#733
Le Mans Master
Member Since: Nov 2015
Location: Lake Havasu City Arizona
Posts: 7,326
Received 3,438 Likes
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2,058 Posts
Well yesterday I joined the club ! My A8 symptom free 2016 with 29600 miles and many road trips from here in Florida to way out west, up north finally gave in. Saturday it started shuttering at speed and yesterday the dealer took it in for a new torque converter. Vehicle was made in late October 2015 just after the supposed cut off date for the known bad components. Good dealership . no problems with service and ready for a road trip to Oklahoma next month!
#734
Instructor
My car began to shudder at around 4000 miles and my dealer said they had to try the flush before replacing the TC. After the flush I drove the car about 500 miles to see if the flush worked (it seemed to) and then I installed the range unit. It is very inconsistent, in my opinion, that some dealers go straight to replacing the TC and others follow a different protocol and insist on doing the flush.
BTW No issues with the TC or the range unit so far.
#735
Le Mans Master
Member Since: Nov 2015
Location: Lake Havasu City Arizona
Posts: 7,326
Received 3,438 Likes
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2,058 Posts
Can I ask the last few digits of your VIN? I think mine was built within a few days of yours. (5109197 here)
My car began to shudder at around 4000 miles and my dealer said they had to try the flush before replacing the TC. After the flush I drove the car about 500 miles to see if the flush worked (it seemed to) and then I installed the range unit. It is very inconsistent, in my opinion, that some dealers go straight to replacing the TC and others follow a different protocol and insist on doing the flush.
BTW No issues with the TC or the range unit so far.
My car began to shudder at around 4000 miles and my dealer said they had to try the flush before replacing the TC. After the flush I drove the car about 500 miles to see if the flush worked (it seemed to) and then I installed the range unit. It is very inconsistent, in my opinion, that some dealers go straight to replacing the TC and others follow a different protocol and insist on doing the flush.
BTW No issues with the TC or the range unit so far.
#737
Instructor
Happy to report that yesterday I picked my car up after the torque converter replacement was completed. It runs like a scalded rabbit again. Total time was four days and the total cost ZERO. Car purchased and work done by Greenwood Chevrolet, Fort Meade, Florida. Danny was the mechanic.
#739
Burning Brakes
I am in the club also. Bought our 2016 Z51 A8 used in January with 19,511 miles. The first few months were fine, in April on a trip to Waco, noticed the shuddering, shifted to M for the rest of the trip. Shuddering has occurred many to times since, can even feel it after driving 10 minutes on the freeway. Contacted my selling dealer in June (about 15 miles away) and they didn't acknowledge right away the problem, they did after I mentioned I had read about it on the internet. Contacted the dealer closest to me (1.5 miles away). They were a little more forthcoming, telling me they have done a few Corvettes and at the time their guy that does them had a 2 week backlog. Car has 22118 miles now. Went by the dealer closest to me yesterday, talked to them in person and was able to bring the car into them this morning for them to look at. We shall see how it goes.
#740
Instructor
It’s really amazing that some forum member attorney hasn’t started the idea of a class action suit. The cost in lost time shuttling back and forth to dealerships as GM continues their experimental repair process is astronomical. Not to speak of the frustration of dealing with the process and in many cases having to arrange for alternative transportation. The transmission is obviously a flawed design. Problems are prevalent in other models in addition to the Corvette. GM has a responsibility to its customers but evidently they will only honor it if forced to do so. It’s time for a jury to decide what’s fair and reasonable since the company doesn’t seem capable of doing so on their own.
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Ridgerunner 7.62 (11-08-2018)