formulaWA

Hi Folks
It appears that DCT failures have been a hot topic on these forums. One thing I have noticed that one thing these failures seem to have in common is that most of them seem to happen at relatively low miles. ie less than 10,000 miles.

I would be interested in comments from folks that have DCT issues at higher mileages. I am curious if for the most part if you make it through the 1st few 1,000s of miles then the Termec tend to be reliable ?

RKCRLR

Most of the DCT failures appear to be infant mortality but I've seen a few high mileage failures posted. We'll know better once there are more high mileage C8s out there. Could take a while, this is Corvette owners were talking about.

Red Mist Rulz

IF the theory that manufacturing debris is the root cause is true, then I would expect most failures to happen at relatively low mileage.

But if that really were the cause, you'd think Tremec and GM by now would have figured out how to make sure any debris is cleaned out.

Vetteman Jack

^ I agree - this has been going on since the 2020 model year - surely they could come up with a cure for the DCT problems by now.

StfDrmsRMadeOf

It’d bet it’s not a issue of figuring it out, they probably have identified the issue and decided it’s cheaper to replace failed units than to avoid the failures in the first place

MCMLVII

Have a 2020, 17,000 miles. Lost mine 5/21/24.

RKCRLR

There may be some truth to this. The DCT is very complex and I suspect that there is not a single cause of the problems but rather multiple problems. On its own each individual problem is probably rare enough that it wouldn't require a fix but fixing all the potential problems may be costly.

V Vette

I assume you also followed the required maintenance? Thanks

MCMLVII

yup

sowega

There doesn't appear to be a common theme, mileage-wise; I've seen just as many posts from 0-1,000 miles as 10,000+ miles.

Red Mist Rulz

FWIW, my 2021 is over 33K, has had 2 filter changes and one fluid change (last month), and (knock on wood) no problems of any kind.

Zormecteon

Not that I have anything to add .....

23K+ miles on '21. .. at about 21.5K .. Check engine light, lost the even number gears. .(Middle of N Dakota) . Drove to nearest dealer (Bismark-200+ miles). Gears came back before I arrived at dealer. He cleared code. No more problem to get home (1300+ miles)

Went to my servicing dealer . There was a TSB on the code (loss of communication) known before I left on my trip. They did their thing. .. No more since.

neogenesis

I’m one of the higher mileage guys. Daily my 2021. At 49K I got Rear axle system off message. Car drove fine, but obviously was not getting the ELSD activating properly. Ultimately dealer and GM decided the valve body needed to be replaced. Several more weeks of national back order on the valve body and GM decided to just swap out the whole transmission. In my case, this actually worked quite well. I got the latest version of the DCT redesigns and GM gave me DCT coverage up to 149,000 miles. I’m now at 63,000 miles and haven’t had any issues since the replacement.

My thought on all of this is that the valve body seems to be the culprit more often than not. I have yet to hear of any catastrophic mechanical failures of the DCT itself.

Sledge Hammer

If it were the valve body, wouldn't it be a lot easier to replace the valve body than the whole transmission?

sowega

Recent reports suggest they're not bothering with valve bodies anymore and going straight to full DCT replacements.

neogenesis

Absolutely. In my instance, as well as others that have reported here, there was a backlog on availability of the valve body. My car sat at dealer for almost 2 months just waiting for the part before they decided it was easier/more cost effective 🤷🏼‍♂️ to just replace the transmission.

I guess I’m hopeful that the valve body can get revised/figured out in the aftermarket eventually because that should be a relatively inexpensive fix down the road as these cars age.

undecided1965

I mean a lot of us don't put that many miles on our cars

neogenesis

Technically it was extended for 5yr/100K miles from the time and mileage of replacement.

gwalsh88

74,000 miles on my early build 2020 and zero issues so far with the car as a whole. Just tires and replacement of the factory battery earlier this year. Fingers crossed my luck holds out!

24RiptideBlue

That’s my vote. The C8 DCT isn’t the only Dual Clutch on the market. I had an S4 ten years ago that had a seven speed DCT and it was great and it had to work with Audi AWD. VW puts DCTs in GTI’s and Porsche has the PDK…. How could they not have figured this out by now…. But at $25k a pop… that adds up fast. I wonder if they are bumping into patents? Something doesn’t make sense. Why let this ruin the best thing gm ever made? 🤷‍♂️.

For gods sake, buy a PDK, reverse engineer it and pay a licensing fee for whatever you need. gm made $10.1Billion last year (income) throw a few million Porsches way and FIX THE TRANSMISSION…

I feel better now…. Nah not really

I have another idea… take five self destructed DCTs and send them to Porsche and ask very nicely (can you fix this so it won’t break?). The German auto industry is known for its metal work. Super strong alloys, and machining to super tight tolerances. My guess it has something to do with either or both of those. The failure of some alloy or parts that need to be to 4 decimal places and they struggle to hold 3…

gm could be using inferior materials and not even know it. Lots of problems with steel and titanium quality in automotive and aviation. Whenever you chase cost too aggressively you have quality lapses.

It just should be resolved by now. Five years is a long time.