Fingers Crossed - A8 Shudder
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Sorry for your troubles. Can I ask you to take a moment to describe a bit more what this "shudder" is. I have seen past posts but not sure I have read a good description. I even took time today to search but I am not very succesful with the search.
I am currently experiencing two things:
1. almost constant fluctuation of RPS up and down in a range of 50-100. Enough for me to feel as the driver. The dealer diagnosed this as a bad tensioner and replacing it helped some. This is the second tensioner replaced.
2. When I accelerate sometimes, especially at highway speeds of 50-75 I think I feel an almost knocking at the point of initial acceleration. This bumping feels like it is coming from the drive shaft and lasts very briefly. The second one cant be recorded or videoed but I feel it in the seat and steering wheel.
Thanks in advance for taking the time.
I am currently experiencing two things:
1. almost constant fluctuation of RPS up and down in a range of 50-100. Enough for me to feel as the driver. The dealer diagnosed this as a bad tensioner and replacing it helped some. This is the second tensioner replaced.
2. When I accelerate sometimes, especially at highway speeds of 50-75 I think I feel an almost knocking at the point of initial acceleration. This bumping feels like it is coming from the drive shaft and lasts very briefly. The second one cant be recorded or videoed but I feel it in the seat and steering wheel.
Thanks in advance for taking the time.
Sadly both 1 and 2 are happening. Dealer thinks it could be the torque converter. They’re going to flush the transmission fluid first per TSB 18-NA-355. It’s just like you described, an odd almost hesitation and jumpy rpm’s. I feel it anywhere between 40 and 70. Look up torque tube, it could be what you’re hearing in #2.
I’ll keep you updated. They’re going to have my car for a week or so.
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Dealer flushed mine, not even the dealer where I purchased the car, at no charge, I paid for a new filter was all. The cost would have been $575. It fixed the shudder and shifts as smooth as butter.
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I dug out my old receipt. Your correct about price. My warranty was long gone, so I had to pay. But it was well worth the $$$
Car has been at the dealer for over a week. I finally get a call saying they couldn’t reproduce the issue. It’s annoying that dealers play this game. For those interested it’s Maher in St Petersburg, FL. I’m still pushing for the transmission flush and replacement of the terrible stock fluid. Anyone have a suggestion for a good dealer in the St Pete/Tampa area? Clearly Maher isn’t the answer.
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Not sure if this related to C7 tramsmission issues presented here, but between taking delivery and my first service, I read that Chevy was not adding enough transmission fluid to their own recommended level. When i took my '14 in for its first service, i ask them to check it - it was way low. So they topped it off.
I wonder if what you are experiencing is somehow related to operating with low transmission oil from the Bowling Green.
I wonder if what you are experiencing is somehow related to operating with low transmission oil from the Bowling Green.
Not answering your question about a dealer recommendation in Tampa area... BUT, I just had this service done on my 2017. It was out of pocket for the Mobil 1 flush as the warranties have expired. I actually spoke to 2 local Chevrolet dealers AND a GMC/Buick dealer in my area. None of the 3 dealers I spoke to even hinted at acting like they might not do the fix. From my understanding, they were ALL aware of the Service Bulletin GM has out on the 8-speed transmissions. This issue affects more than just the Corvette... they are doing these flushes on all sorts of vehicles. I can't believe a dealer would decline doing the transmission flush knowing the TSB and probably doing these flushes regularly. Dealers can be so frustrating!! A good one makes all the difference! Good luck.
Yeah, I’m done with these clowns when I get my car back tomorrow. I’ve got a road trip coming later this week and will get it looked at again at a dealer where I’m heading that I trust. I was even willing to pay for it and they still thought I should wait. It makes no sense. They also expressed how short handed they are right now. Maybe it was too time consuming? Who knows.
Got the car back today. They ran some software updates for the transmission and the infotainment system, changed the oil, and fixed a evap solenoid issue. So far it feels ok. Still not thrilled they wouldn’t flush the transmission.
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It is possible that something in the diagnostics told them it was something else. If its ok now, I wouldn't worry. Does it again, they will have no choice.
They said that it’s something they can typically induce and they couldn’t. Mind you they only drove the car 5 miles. I really only notice the shudder 1 out of 10 times driving. So it’s very intermittent. They said not to worry about it until it really becomes a regular thing. I was more concerned because I’ve got a 1200 mile road trip starting tomorrow and wanted to make sure I didn’t end up breaking down for some reason (would be my luck). Plus, I haven’t felt confident in driving more aggressively due to the shudder. Like I’m going to grenade the transmission. I’m probably overthinking it. Again, thankful I have an extended warranty.
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269 Posts
At least now its on the books. Something happens, they can't blame you.
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Had 2 C7's, both had A8 issues, shudder, hard shifting, no shifting when cold. Traded both in, GM would not fix, said they could not repeat, then said it needed a module refresh and to drive 500 miles to see if fixed. They finally, after 18 mos, changed the torque converter on the first one and then dropped the whole tranny on the ground because it was not supported correctly, said they put in a new one, but it was never right, I gave up. If you have issues, GET RID OF IT. Or find a lawyer, a GM mechanic told that to me. GM knew the A8 has issues but still kept producing. Dealer one time told me I was driving incorrectly, whatever that means.
Oh man. Crazy that you had to take such drastic measures. If this keeps up I’ll be following suit. This is my first GM product in 20 years and it’s leaving a bad taste in my mouth. I literally told the dealer this could be the worst transmission I’ve ever driven. He had nothing to say. Probably because he knew I was right. Thanks for your insight.
There is a Service Bulletin that covers your issue. It’s Bulletin # 18-NA-355. Covers all A8 equipped models from 2015 to 2019. If you were denied or paid for a flush you should get a refund or have it performed free.
Yeah, that dealer didn’t think it was enough of an issue yet. Whatever that means. That said, I’ll be going to a different dealer going forward. These guys weren’t very helpful.
If you can feel the shudder holding your shifter put a 2/3s full water bottle in the cup holder and record it on your phone. The turbulence in the water bottle should convince them. This is how I proved a rejected claim of unbalanced tires to my tire dealer. Good luck.
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