I became so frustrated with my 2024 C8's noisy transmission, that I traded it in on a 2025. Thought it would end the irritation. Wrong! This car does other weird things like dropping out of gear momentarily while you're at a stop, and jerking back in. No trouble lights, haven't gone to dealer over this (yet). I. guess I'm hoping the filter change/oil change might affect this for the better. Getting close to being over this whole C8 thing.

 

Im not in the DCT failure club (yet), but, no, I see no indication that GM has done anything to fix the problem based on the volume of comments here as well as the fact that my local dealer told me two weeks ago that they ALWAYS have a bunch of new C8's being disassembled for DCT replacement all the time.

 

The Consumer Reports survey shows C8 transmission reliability about average so the failure rate is on par with other cars. The main problem with the DCT problems is how long it can take a dealer and/or GM to fix a problem once it occurs.

 

I was in to see my sales guy a couple weeks ago and also my service advisor while I was completing a extended warranty. They are a big Vet dealer down here in South Florida. They told me that they haven’t seen too many DCT‘s fail since about 2022. they both independently at different times says that they didn’t see it as a problem with the car currently…

 

I haven't heard of any noisy DCTs, that's a new one. Not sure what would be noisy, it's a MT with computer controlled clutch and shifting.

 

SAME ON MY 2025 -- bought in June..only 2800 miles so waiting for first service

 

How many miles on the 25? Is it getting any better or are the issues constant.
Do these transmissions have the ability l to learn your driving style and make adjustments?

 

DC failures are not as prevalent as you might think. The people with the failures come forward and are vocal compared to vast majority that are happily driving.

 

I own a 2020 C8. I worry about the transmission but haven't had any problems. Problem there is though..I barely drive the car. I wish I could find out who owned the car before me so I could talk to him. Does anybody know how I could find out that information? Or is it considered an invasion of privacy for me to have that info?

 

I don’t think it’s a big issue. But different in this car is there is no repair, you need a new one. Hopefully someone, won’t be gm will figure out how to repair them. But that won’t happen until there is a demand for repairs…..meaning lot of failures. 3rd parties have filled this void in the pass. That may happen soon as cars will need repair out of warranty and there will be a market


Drive it don’t worry

 

Thanks

How much do we know about the TR-9080 from Tremec? I remember Tremec made the T-56 and put it in the SS/Z28 Camaro, Firebird, and likely a host of other vehicles. That was a damn fine transmission. But of course, being a manual transmission, they were very straightforward and very different than the DCT we have, with all its complexities.

I wonder if these transmission issues are all different with varying points of breaking, or if they are all following the same pattern and settle on one weak point. I don't have any information on it. But I sure would love to see a 3D diagram of the DCT and how it works.

Does anybody know if the TR-9080 is put in any other vehicles besides the C8? What about the differences between a Z06/ZR1 compared to a Z51? I was wondering if they beefed the transmission up for those models. Thanks for your knowledge and help!

 

I think the TR9080 is pit in the Ford GTD. I know the GTD has a Tremec DCT. I saw a Utube with a Tremec guy describing the 9080 say so. That’s a $350,000 car.

 

And the Tremec rep said the variant in the ZR1 was beefed up to handle the 850 ft-lbs of torque.

 

im up to 3500 miles of driving, ive been thoroughly beating its brains out since 1500 miles was up. no issues so far. but i am worried about how the clutch wears over time. ive heard people that have like 20k or 30k miles started to get some jerkiness at low speed, like it feels like maybe slip and grabyness an old clutch can get. anyone experience anything like that? also of course ive seen the horror stories and worry, but so far no lights. every now and again i feel like i get a slow shift, and thats pretty much it.

 

fantastic info, thank you!

 

So I started one Thread about engine and transmission shudder and then added comments to another one regarding the same concerns. It might not be your transmission that is having the problem. There is a service bulletin for the camshaft actuator magnet. It is for all 2014 through 2025 C8s, LT1 & LT2 6.2 L engines. It is really for any of those Motors including those in cars and trucks.

22-NA-080 is the Bulletin. I will try to attach it here. The original bulletin came out in April 2022. An update, to take the service notice through the 2025 yeat models, just came out on September 5, 2025.

They can run a test and if it is out of balance by more than 3°, it has to be replaced. My car was shuddering and jumping badly in low gears especially when cold started. Once it warmed up, you didn't feel it as much. However, it was still there. They tested mine and it was way out of balance. Guess what? The entire motor has to be dropped and multiple components have to be removed so they can get into the interior of the motor and replace the stupid magnet! Mine is scheduled for the week September 29th.

Not happy at all, but mine is covered under warranty and I would think most would be covered under warranty considering it's part of the drivetrain. My main concern is the motor and all the components being put back properly, in a good working order, and I don't have any residual side effects or problems from any type of negligent or poor service.

Sigh.....

 

I wonder if they will ever consider bringing back the manual 6 speed.

 

Gawd, I hope not...

 

You stand a better chance at meeting God.

 

Love my C8, but I do miss doing my own shift work. Previous Vette was a base model C6 with M6 tranny and enough engine mods to see 500 at the wheels. Whole lot of fun. My left knee isn't what it used to be though. C8 was the natural progression for me.