A8 Transmission Problem? Help Diagnose Please :)
04-25-2018, 12:48 AM
#21
I’ve had this issue since about 3,800 miles on my 2015 A8. If your issue tracks with mine, it will get worse. Wait for a month or two until it’s more pronounced and take it back. The dealer was never able to fix mine after five tries and GM finally threw in the towel and is replacing my car with a new 2019. Good luck.
Assuming you had to repay taxes and licensing? or did GM cover that too? Did you get a new 3 year warranty?
Last edited by CorvetteCali; 04-25-2018 at 12:53 AM.
04-25-2018, 02:09 AM
#22
Instructor
I bought mine brand new with 7 miles on it. Mine as been doing it for as far back as I remember. The issue has not got any worse for me. Now, I have just about 12000 miles on it. In the past, I told the dealer about it and they updated the transmission software. If you ask me, none of the updates the dealer did made any difference.
04-25-2018, 04:01 AM
#23
04-25-2018, 06:30 AM
#24
Burning Brakes
I’m very easy on my C7 until things are warmed up. I usually drive away from my place very gingerly for the first block or two. That’s when I noticed that first abrupt shift. I’ve found that if I pull away a bit more aggressively, (nothing ridiculous mind you) I sometimes don’t have the problem. The ultimate cure has been to just use the paddles for that first couple of shifts. It’s always been smooth that way.
04-25-2018, 08:16 AM
#25
I’m very easy on my C7 until things are warmed up. I usually drive away from my place very gingerly for the first block or two. That’s when I noticed that first abrupt shift. I’ve found that if I pull away a bit more aggressively, (nothing ridiculous mind you) I sometimes don’t have the problem. The ultimate cure has been to just use the paddles for that first couple of shifts. It’s always been smooth that way.
paddle the first few
04-25-2018, 09:51 AM
#26
Safety Car
Had a different issue w my 2016 Z51, with 6000 miles on it, A8 today. I was driving in Sport mode on the interstate for 10 minutes or so (everything should be warmed up by now) at the posted limit when a tractor trailer driver decided to squeeze me, causing me to depress the go pedal A LOT! The acceleration from 60 to nearly 80 was impressive and the tractor trailer was nicely disappearing in the rear view mirror! But when I let off the gas pedal due to traffic ahead the RPM's remained noticeably high (4K) for an uncomfortably long period of time. After 15 seconds or so the RPM's dropped to back cruising speed. Do I have an A8 problem???? What say ye?
Do you guys even read the manual?
04-25-2018, 10:29 AM
#27
Le Mans Master
The complaints are certainly out there which is the RPM variation and shudder at steady cruising speed with the engine running in V4 mode and the lockup clutch no longer engaging as consistently as it should (and did when new). During V4 mode the lockup clutch is rapidly modulated on and off to help absorb V4 mode vibration and the amount of wear that occurs in a few hundred miles in this mode is more than you would normally see in a very well used transmission.
It is covered under warranty (see all of the replacement torque converters, triple fluid flush, new fluid type, etc.). The problem is worse with the LT1 because it goes into V4 mode quite frequently under cruising conditions while the problem is seldom seen with the LT4 equipped Z06 which goes into V4 mode only under very limited conditions.
The same problem shows up in other GM platforms using this transmission and AFM system and it seems worse with the 8L90 transmission probably because the torque converter was shrunk so that the 8L90 could fit within the same length/ space as the 6L80 6 speed.
It is covered under warranty (see all of the replacement torque converters, triple fluid flush, new fluid type, etc.). The problem is worse with the LT1 because it goes into V4 mode quite frequently under cruising conditions while the problem is seldom seen with the LT4 equipped Z06 which goes into V4 mode only under very limited conditions.
The same problem shows up in other GM platforms using this transmission and AFM system and it seems worse with the 8L90 transmission probably because the torque converter was shrunk so that the 8L90 could fit within the same length/ space as the 6L80 6 speed.
I'm trying to find the GM Part Number for this Gen 3 TC. Any help appreciated.
04-25-2018, 11:00 AM
#28
I also put it in your post.
04-25-2018, 11:24 AM
#29
Team Owner
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St. Jude Donor '13
04-25-2018, 09:05 PM
#31
Heel & Toe
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CorvetteCali (04-27-2018)
04-25-2018, 09:19 PM
#32
Instructor
GM pays for everything
GM covers the entire cost. They pay off the loan and cover the cost of a new car. They also cover the tax and license. I get a new warranty. The only thing I’m subject to is a fair use fee that covers the time I had the car before the issue was first reported. It will amount to two or three thousand, I think. Not a bad deal.
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CorvetteCali (04-27-2018)
04-27-2018, 02:34 AM
#33
GM covers the entire cost. They pay off the loan and cover the cost of a new car. They also cover the tax and license. I get a new warranty. The only thing I’m subject to is a fair use fee that covers the time I had the car before the issue was first reported. It will amount to two or three thousand, I think. Not a bad deal.
04-27-2018, 11:07 AM
#34
Burning Brakes
I've got 11K on my 2016 and it has had the rough 1-2nd shift on cold days since day 1. On warm days, like 70-90s there is no problem. I shift it intoM after i back out of the driveway and select 2nd gear when driving off. FWIW i had a sticky manual shift from 1st to second on cold days on a previous car. I had to be careful not to grind em until it warmed up. Put 125 miles on it with no problems. I think it is just the increased viscosity of the cold fluids. When I first got the vette i was worried that after sitting for a while it would crank for what I thought was too long, then I found out that the fuel rail needs to get up to pressure before ignition. These new fangled machines with all their computers can be so confusing some times especially for old geezers.
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CorvetteCali (04-30-2018)
04-30-2018, 11:39 PM
#35
I've got 11K on my 2016 and it has had the rough 1-2nd shift on cold days since day 1. On warm days, like 70-90s there is no problem. I shift it intoM after i back out of the driveway and select 2nd gear when driving off. FWIW i had a sticky manual shift from 1st to second on cold days on a previous car. I had to be careful not to grind em until it warmed up. Put 125 miles on it with no problems. I think it is just the increased viscosity of the cold fluids. When I first got the vette i was worried that after sitting for a while it would crank for what I thought was too long, then I found out that the fuel rail needs to get up to pressure before ignition. These new fangled machines with all their computers can be so confusing some times especially for old geezers.