C8 problems
Instructor
Joined: Nov 2020
Posts: 239
Likes: 195
My C8 had no problems today. But I also haven't driven it.
Drifting
Joined: Apr 2014
Posts: 1,458
Likes: 625
From: Southeast, FL.
I hope that this all and the problem is solved without having to replace the transmission.
8th Gear
Joined: Jun 2021
Posts: 8
Likes: 7
From: Las Vegas
When I picked up my car on Saturday, there were 2 other C8's at the dealer that were being repaired for transmission problems. A lot of the issues just aren't being reported.
Put a 100 miles on the car yesterday....drove around Lake Mead, it was a mild 120 degrees out! Keeping my fingers crossed for no more leaks!
Dronepilot
Put a 100 miles on the car yesterday....drove around Lake Mead, it was a mild 120 degrees out! Keeping my fingers crossed for no more leaks!
Dronepilot
Advanced
Joined: Jun 2009
Posts: 90
Likes: 31
From: Redmond, WA
I have been closely following this discussion on the transmission and I am really concerned. Irrespective of the percentage of units having problems (I do feel that the numbers are simply to high), what worries me is how GM service is handling their halo car? I am seriously considering either waiting another two years or so, or looking at Porsche. I still have memories of the problems I had with a leaky transaxle in my 99 C5. It was never really resolved. I just don't see how so many 100K cars can stay in the shop for so long as GM figures this out. And let's face it, Chevy dealers are no known for their service! 
Drifting
Joined: Feb 2017
Posts: 1,778
Likes: 902
When I picked up my car on Saturday, there were 2 other C8's at the dealer that were being repaired for transmission problems. A lot of the issues just aren't being reported.
Put a 100 miles on the car yesterday....drove around Lake Mead, it was a mild 120 degrees out! Keeping my fingers crossed for no more leaks!
Dronepilot
Put a 100 miles on the car yesterday....drove around Lake Mead, it was a mild 120 degrees out! Keeping my fingers crossed for no more leaks!
Dronepilot
I just read a facebook post.
Update* Hell everyone, my late 2020 model year last month had a transmission valve body/ gaskets replaced do to the C8 not downshifting and jumping forward at stops. The past few weeks the transmission was acting up with the same issues but even worse with shutting off at some stops😞 I’ve had the TRANSMISSION oil fluid filled up twice already. What was the outcome of anyone having similar transmission issues?? I have 15,500 miles 90 percent are highway miles in 8 months. Thank you.
Last edited by sprayer; Jul 12, 2021 at 03:38 PM.
Heel & Toe
Joined: Jul 2018
Posts: 23
Likes: 30
From: Gladstone Michigan
I am on day 4 with my 2021 HTC and I LOVE the car. However, when driving at lower speeds from about 20 to 45 with the top down I hear a "rattle" or a "crackling" sound up high between the head rests. It seems to be closer to the passenger seat or the center speaker between the seats. Nothing is there that I can see. I put my hands on the speaker grille but nothing changes. I tried pulling out the passenger seat belt a little more but it didn't help. It doesn't matter if the radio is playing or not. Once you get up to about 50 there is no more noise. With the top up there is no problem at any speed. Anyone else having a similar issue? Anything I should be looking for?
Racer
Joined: Mar 2014
Posts: 321
Likes: 84
From: Marco Island FL
You expect GM to replace 60,000 transmissions when a handful had failures? Please....that's a bit different than the 20 engines mentioned in the article.
Also, read the recall notice. It states:
"Porsche will either replace the connecting rods or the entire engine in the affected vehicles."
While the article states that a Porsche spokesperson did say all 20 delivered engines would be replaced, would be surprised if they planned to do so but did not so state in the recall notice, which is the official documentation on the matter. And even if they did, 20 is a far cry from the tens of thousands of released Corvettes. I agree that better QOR would be nice, but the point is that as shown in both cases, sometimes things slip through, just seems like Porsche caught theirs earlier (and also, a grenading engine is a much higher safety concern than a slipping or leaking transmission, hence the stronger response).
Also, read the recall notice. It states:
"Porsche will either replace the connecting rods or the entire engine in the affected vehicles."
While the article states that a Porsche spokesperson did say all 20 delivered engines would be replaced, would be surprised if they planned to do so but did not so state in the recall notice, which is the official documentation on the matter. And even if they did, 20 is a far cry from the tens of thousands of released Corvettes. I agree that better QOR would be nice, but the point is that as shown in both cases, sometimes things slip through, just seems like Porsche caught theirs earlier (and also, a grenading engine is a much higher safety concern than a slipping or leaking transmission, hence the stronger response).
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Advanced
Joined: Sep 2020
Posts: 63
Likes: 52
New to Forum...
2020 C8, currently has 3000 miles on it and in the shop. Found 2 puddles under the rear wheels, one was about an ounce of fluid, very dirty. Second puddle was about 6 ounces and clear, as if just poured out of the bottle. Taken in to the dealership this morning. Diagnosis is leaking transmission pan seal. This is the second time for this problem, first was at 1300 miles. Car is a daily driver. GM Tech is involved....so will see what happens. Current plan is to clean it up, reseal, drive till hot then let sit over night and evaluate in the morning. Will update as I find out more.
Dronepilot
2020 C8 LT2 with competition seats and front lift
2020 C8, currently has 3000 miles on it and in the shop. Found 2 puddles under the rear wheels, one was about an ounce of fluid, very dirty. Second puddle was about 6 ounces and clear, as if just poured out of the bottle. Taken in to the dealership this morning. Diagnosis is leaking transmission pan seal. This is the second time for this problem, first was at 1300 miles. Car is a daily driver. GM Tech is involved....so will see what happens. Current plan is to clean it up, reseal, drive till hot then let sit over night and evaluate in the morning. Will update as I find out more.
Dronepilot
2020 C8 LT2 with competition seats and front lift
Drifting
Joined: Feb 2017
Posts: 1,778
Likes: 902
You expect GM to replace 60,000 transmissions when a handful had failures? Please....that's a bit different than the 20 engines mentioned in the article.
Also, read the recall notice. It states:
"Porsche will either replace the connecting rods or the entire engine in the affected vehicles."
While the article states that a Porsche spokesperson did say all 20 delivered engines would be replaced, would be surprised if they planned to do so but did not so state in the recall notice, which is the official documentation on the matter. And even if they did, 20 is a far cry from the tens of thousands of released Corvettes. I agree that better QOR would be nice, but the point is that as shown in both cases, sometimes things slip through, just seems like Porsche caught theirs earlier (and also, a grenading engine is a much higher safety concern than a slipping or leaking transmission, hence the stronger response).
Also, read the recall notice. It states:
"Porsche will either replace the connecting rods or the entire engine in the affected vehicles."
While the article states that a Porsche spokesperson did say all 20 delivered engines would be replaced, would be surprised if they planned to do so but did not so state in the recall notice, which is the official documentation on the matter. And even if they did, 20 is a far cry from the tens of thousands of released Corvettes. I agree that better QOR would be nice, but the point is that as shown in both cases, sometimes things slip through, just seems like Porsche caught theirs earlier (and also, a grenading engine is a much higher safety concern than a slipping or leaking transmission, hence the stronger response).
Drifting
Joined: Jun 2021
Posts: 1,294
Likes: 752
From: Phoenix, Arizona
Racer
Joined: May 2008
Posts: 399
Likes: 199
OK, call it 40,000, I don't have precise production figures available for the C8, and that really wasn't the central point of my argument...point is, that Porsche replacing 20 engines is a bit different than GM replacing all transmissions for the entire production run.
Racer
Joined: May 2008
Posts: 399
Likes: 199
Just shows Porsche take things more seriously and do the right thing for their customers. If blowing of an engine is a high safety concern and warranted Porsche to address it, the same cannot be said for GM when they had LS7 engines blowing up like fire crackers in much bigger quantities than 20. GM are great at slipping out of holding and liability for the products they sell. They pass that burden and cost onto their loyal customers.
Also, despite all of their "track ready" advertising, Porsche's warranty is voided if vehicle is used in track events , thus "slipping out of holding and liability for the products they sell" (See p5-6, second column of p6). But GM *does* honor the warranty in this case, for Z51 equipped C8s and certain Camaros , thus "doing the right thing for their customers".
Also also, maybe you missed my question about what car you happen to drive? You spend tons of time here trolling and bashing Vettes, so I'm sure you don't drive one, what do you drive? Please, enlighten me.
Last edited by improviz; Jul 15, 2021 at 09:46 AM.
Melting Slicks
Joined: May 2021
Posts: 2,562
Likes: 1,579
I am on day 4 with my 2021 HTC and I LOVE the car. However, when driving at lower speeds from about 20 to 45 with the top down I hear a "rattle" or a "crackling" sound up high between the head rests. It seems to be closer to the passenger seat or the center speaker between the seats. Nothing is there that I can see. I put my hands on the speaker grille but nothing changes. I tried pulling out the passenger seat belt a little more but it didn't help. It doesn't matter if the radio is playing or not. Once you get up to about 50 there is no more noise. With the top up there is no problem at any speed. Anyone else having a similar issue? Anything I should be looking for?
Melting Slicks
Joined: Mar 2005
Posts: 2,534
Likes: 118
From: Columbia, SC
Drifting
Joined: Apr 2021
Posts: 1,560
Likes: 1,074
IMS bearing failure
Refresh my memory on how Porsche handled the IMS bearing failure. I believe they left it to outside after market vendors to design a better bearing and have the customer pay $4,000 to install it?
Just shows Porsche take things more seriously and do the right thing for their customers. If blowing of an engine is a high safety concern and warranted Porsche to address it, the same cannot be said for GM when they had LS7 engines blowing up like fire crackers in much bigger quantities than 20. GM are great at slipping out of holding and liability for the products they sell. They pass that burden and cost onto their loyal customers.