A8's and Torque Converter failure
02-02-2018, 09:04 AM
#601
^^^
If the lurch occurs after an abnormal delay to engage R or D when cold it may be another issue found in A8s involving not the TC but the stator shaft. See #16-NA-14. I don't know about shuddering in low gear, as the usual TC issues occur in higher gears and V4 mode at cruising speeds during light acceleration.
If the lurch occurs after an abnormal delay to engage R or D when cold it may be another issue found in A8s involving not the TC but the stator shaft. See #16-NA-14. I don't know about shuddering in low gear, as the usual TC issues occur in higher gears and V4 mode at cruising speeds during light acceleration.
02-02-2018, 10:08 AM
#602
Melting Slicks
02-02-2018, 03:12 PM
#604
Melting Slicks
Do you have any trouble getting stuff warranty replaced after having a tune?
02-03-2018, 09:15 AM
#605
A8 and TC failure
can I ask who is your dealer?
After unknowingly having several symptoms of torque converter failure I finally located a dealer who properly diagnosed my transmission problem as a bad o-ring in the torque converter. A new torque converter will be installed next week. I have a 2015 A8 born October 2014 and noticed a problem with the transmission at about 10K miles. I decided to do a little research into the symptoms of a bad torque converter and have included a partial list.
(1) - Surging and Lugging - Your car can't seem to maintain constant speed. I noticed this especially when in cruise control (in V4) and your RPMs go up and down. In cruise control, on a level surface, you should seen very little movement in your RPMs.
(2) - Shuddering - Feels like you are running over a rough road when you are on a smooth road. Comes and goes without warning. Mine did this and I thought my front tires were out of balance.
(3) - Vehicle Lurches - Mine did this maybe 3-4 times when at slow idle.
(4) - Slow to go into gears including reverse. Mine was slow to go into reverse.
(5) - Gears don't shift easy.
(6) - Strange Noises - Clicking or revving.
(7) - Gears Slipping - Loss of acceleration.
(8) - Overheating.
Hope this info helps other A8 owners who might be having torque converter problems and not know it.
(1) - Surging and Lugging - Your car can't seem to maintain constant speed. I noticed this especially when in cruise control (in V4) and your RPMs go up and down. In cruise control, on a level surface, you should seen very little movement in your RPMs.
(2) - Shuddering - Feels like you are running over a rough road when you are on a smooth road. Comes and goes without warning. Mine did this and I thought my front tires were out of balance.
(3) - Vehicle Lurches - Mine did this maybe 3-4 times when at slow idle.
(4) - Slow to go into gears including reverse. Mine was slow to go into reverse.
(5) - Gears don't shift easy.
(6) - Strange Noises - Clicking or revving.
(7) - Gears Slipping - Loss of acceleration.
(8) - Overheating.
Hope this info helps other A8 owners who might be having torque converter problems and not know it.
02-03-2018, 12:53 PM
#607
Le Mans Master
Those interested in the A8 torque converter should vote in this month’s “Ask Tadge” poll. Specifically poll question#4, 4 Different Torque Converters.
https://www.corvetteforum.com/forums...-2-4-18-a.html
https://www.corvetteforum.com/forums...-2-4-18-a.html
The following 2 users liked this post by Maxie2U:
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02-03-2018, 02:40 PM
#608
Those interested in the A8 torque converter should vote in this month’s “Ask Tadge” poll. Specifically poll question#4, 4 Different Torque Converters.
https://www.corvetteforum.com/forums...-2-4-18-a.html
https://www.corvetteforum.com/forums...-2-4-18-a.html
...........excellent question in the "ask Tadge poll",
02-03-2018, 03:11 PM
#609
Melting Slicks
I noticed it early on and it occurred only about once every three months, almost like clockwork. Thus, I could never demonstrate it to a dealer. When my TC was replaced they wouldn't do the stator fix because they couldn't duplicate it, even though the tranny was out of the car for the TC fix and doing the other repair would've been rather quick and easy. I just let it go as an innocuous aggravation and I don't think it's something that would cause more serious problems. My solution to my A8 problems was to buy a 2017 with an M7. The disturbance in the force is gone and all is well now.
02-06-2018, 09:15 AM
#610
Racer
My 2017 GS has only 1900 mileage and I had yesterday a 3 hours drive with it and I had never paid attention before, but, I found that on interstate, at steady speed between 70 and 80mph, there are rpm variations. No more than 50 max, I think, but a variation still visible on the counter.
It seems not to do when I switch to manual mode. I did not notice anything else.
Is it the beginning of a failure?
It seems not to do when I switch to manual mode. I did not notice anything else.
Is it the beginning of a failure?
Last edited by Flo; 02-06-2018 at 09:18 AM.
02-06-2018, 10:08 AM
#611
Melting Slicks
The constant oscillation from engaging and disengaging the torque converter clutch will cause accelerated wear to the clutch. When this occurs I would put it in M to make it last longer.
02-06-2018, 10:59 AM
#612
Burning Brakes
02-06-2018, 05:38 PM
#613
Safety Car
Thread Starter
My 2017 GS has only 1900 mileage and I had yesterday a 3 hours drive with it and I had never paid attention before, but, I found that on interstate, at steady speed between 70 and 80mph, there are rpm variations. No more than 50 max, I think, but a variation still visible on the counter.
It seems not to do when I switch to manual mode. I did not notice anything else.
Is it the beginning of a failure?
It seems not to do when I switch to manual mode. I did not notice anything else.
Is it the beginning of a failure?
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02-06-2018, 06:21 PM
#615
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I remember reading about a discussion a GM Eng. had last year at the BGreen Corvette Bash stating it was not uncommon to see some RPM fluctuations. The TC is pretty active so some fluctuations maybe OK. Just passing on what i read have no clue if it is factual.
02-06-2018, 06:25 PM
#616
My 2017 GS has only 1900 mileage and I had yesterday a 3 hours drive with it and I had never paid attention before, but, I found that on interstate, at steady speed between 70 and 80mph, there are rpm variations. No more than 50 max, I think, but a variation still visible on the counter.
It seems not to do when I switch to manual mode. I did not notice anything else.
Is it the beginning of a failure?
It seems not to do when I switch to manual mode. I did not notice anything else.
Is it the beginning of a failure?
I have a Z06 and a 50 RPM variation at typical interstate speed would result in around a 2 MPH speed variation; if you in varying load conditions (i.e. windy day) and see the speedometer drifting up or down in this range and it follows RPM changes then I wouldn't be overly concerned. But if the car is under steady load but you still see the RPM varying with steady speed it is a pretty good sign the torque converter clutch is at least in the early stages of having a problem and it will get worse.
I never let my Z06 go into V4 mode. Without the ridiculous AFM system going active the A8 is a pretty impressive transmission and although the gains may be higher with the LT1 running V4 mode a few posts I have seen show that in the Z06 at most it nets maybe 1 MPG. It is too bad the U.S. cars aren't like the Euorpean spec auto that only goes into V4 in eco mode just like the manual version.
02-06-2018, 06:29 PM
#617
Racer
How can you avoid to let your vette go into V4 mode?
What I found during the last drive of my GS, is that the car was in a steady load, with speed regulator, when the RPM had variations. And these variations were in sport mode and also without the speed regulator. In these case it seemed more accentuated.
During the return trip, I will be more attentive.
What I found during the last drive of my GS, is that the car was in a steady load, with speed regulator, when the RPM had variations. And these variations were in sport mode and also without the speed regulator. In these case it seemed more accentuated.
During the return trip, I will be more attentive.
Last edited by Flo; 02-06-2018 at 06:36 PM.
02-06-2018, 06:43 PM
#618
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How can you avoid to let your vette go into V4 mode?
What I found during the last drive of my GS, is that the car was in a steady load, with speed regulator, when the RPM had variations. And these variations were in sport mode and also without the speed regulator. In these case it seemed more accentuated.
During the return trip, I will be more attentive.
What I found during the last drive of my GS, is that the car was in a steady load, with speed regulator, when the RPM had variations. And these variations were in sport mode and also without the speed regulator. In these case it seemed more accentuated.
During the return trip, I will be more attentive.
02-06-2018, 09:10 PM
#620
I have all of those symptoms minus slipping and overheating and my dealer won’t do squat. They won’t even fix other parts of the car such as my trim coming off and temperature control **** seizing up. Is there anyone I can contact in Canada to express my frustration? Don’t dealers get paid by GM to perform warranty work?