Wow! Microscopic particles so small you can’t even see um. Pretty mysterious….And what are these little particles?? Are they Metal Filings? Clutch Material? A Virus? Bacteria? So 3 years have gone by and we still don’t know what these little particles are or why they are making transmissions die…How could we still all be totally in the dark about what is really going on?? I wonder if the trans fluid has a foul odor? Maybe someone with a microscope should pull the dipstick and look at the fluid and see if they can identify those particles you can’t see…

I Know…It’s Complicated

I hope they don’t allow chewing tobacco on the assembly line??

 

I’ll bet it is!

but to expand on my first post ….with the c5 pop up headlights…. Gm used nylon gears. They wore out and one could buy aftermarket brass gears for an easy fix. Gm kept using nylon gears. Same with the rocking seats. In the 7 years of c5 production they did nothing to fix the most simplest of issues, I just wonder if they are doing anything or are changing anything with their most complicated transmission?

It is year 4. If one ownes a 10 yo c8 how comfortable will you be? I know I’ll never have one out of warranty.

 

The poll is flawed from the standpoint that you don't know how many folks each year had no problems. If you know for each year how many folks had no problems, then you would be able to tell year by year if the problem is getting worse or better.

For example, there are a total of 9 2022's in the poll that had the trans replaced. There were 25831 total C8's produced in 2022. The poll implies 12% or 3100 of those cars needed to have their transmissions replaced. Granted I have no data on the actual number of DCT's replaced for 2022 models, but I think most would agree that there were not 3100 (or anything even close to it) transmissions replaced.

 

I picked up my 2022 this past March from the NCM and had the CEL come on 110 miles from my house. Issue was the transmission, but it didn’t require replacement. The dealership cleaned the solenoid and flushed the transmission and I haven’t had a problem since, with now several road trips in over 10k miles.

My advice to anyone is to remember that it’s a car and things don’t always go perfectly with every C8, despite the price point. Most C8s coming off the line will experience no problem at all. As has been noted, this is what warranties are indeed for.

The spotlight fallacy doesn’t do anyone any good and distorts the issue a small percentage of owners have as being something to be overly concerned about even before purchasing a C8.

 

1. sorry for your mechanical misfortune
2. rare event considering all vehicles manufactured
3. you have a warranty and a company that actually honors it
4. extremely inexpensive and long-lived extended warranty now available
5. none of the above, except for the first and second (in GREAT Quantity) exists in the RV industry - consider yourself lucky if you do not own one or ....

 

Easy one to answer. As with the engine, small particles will displace themselves during the break in period. With the transmission, the particulates could be the clutch plates breaking in. But unlike the engine, there isn't a valve body that is susceptible to very fine particles that can plug up the pressure sensors. GM/Tremec is trying to get to the bottom of it or they wouldn't have asked the dealers to send ALL DCT filters in a plastic bag for inspection/dissection. And oh by the way, the DCT doesn't have a dipstick.

As I stated in my previous post, they have already made changes to the DCT for other issues that have come to light. So they aren't sticking their heads in the sand. As others have said, if we took a poll of all C8's on the street the percentage of DCT replacements would be much lower than this unscientific poll on this site. And if you think the Corvette is the only car with problems you would be wrong. My Honda Pilot has spent more time in the shop than my Vette for the infamous radio crackling sound. After 4 trips to the dealer over the course of one year they have finally come up with a fix. Although it took Honda nearly three years to come up with that fix.

 

If you are focusing on the small number of owners who have transmission issues to make your decision to buy a C8 then you’ll never buy one.

 

Someone brought up a good point earlier. How can I be assured that the "new" tranny being installed is in fact a "brand new" tranny and not a refurbished one? Any thoughts here as to how I can confirm this. I have the case file opened with GM as soon as the first CE light went on so everything is being documented directly to the factory. I left a voicemail for the case manager at GM regarding this question and am awaiting his response.
Also just to note I also purchased the tire & rim package and the extended warranty when I bought it brand new.

 

Ok, so you are advising someone else not to worry as that's what warranty is for, yet you are worried about the same issue to the degree that you are not purchasing the C8 you desire. That's a bit hypocritical don't you think.

 

With regards to your question in bold above. You quoted me yet in my post I did in fact list three things they have or are doing/have changed to improve the transmission. And it wouldn't surprise me if they continue to improve things after dissecting the DCT filters that were returned to them from the dealers.

 

I'm pretty certain that there are no refurbished tranny's circulating - at least GM ones. These are a complex unit requiring special tooling during assembly to get everything aligned as it should be and I sincerely doubt that even the after-market has invested in the necessary tooling at this stage.

When I had my trans replaced the dealer gave me a heads up and I was there when they un-crated it. The new unit had a build date and date stamps on various components and so I was very certain that it was a new unit. Given that anything can be forged, etc., etc., I guess that GM could have passed off a refurb unit as a "new" one, but why they would do this is beyond me, and I am personally satisfied that the tranny I received was a new one. (Someone can chime in on warranty contract law but I do believe that the auto manufacturers can use refurbished/as-new major components if they choose to).

My original trans had a porous case and my real reason to want to see the replacement trans was to inspect the suspect area to be as sure as possible that I wouldn't get another porous case. I never had any CEL's or other codes, and never had any visible leakage to the ground. I found the leak because I chose to be proactive in replacing the DCT filter at 2,500-miles otherwise I may have continued on until the 7,500-mile service before a leak was found.

This was my first GM vehicle ever and also the "biggest" major component warranty failure I have experienced in +50-years. Disappointed? Yes! BUT I was fortunate in selecting a servicing dealer who was not only very customer focused but was also very Corvette-focused, and had several techs who had done several of the C8 trans changes already. And has been mentioned, I figured that the worse case would be to sell it after repairs.

Also note that there are two case numbers that you need; there is the one that you originate with GM but you also need the one that your dealers service department will have raised with GM. They are different numbers.has been mentioned, I figured that the worse case would be to sell it after repairs.

Also note that there are two case numbers that you need; there is the one that you originate with GM but you also need the one that your dealers service department will have raised with GM. They are different numbers.

Here are examples of tags on the trans; you can decode you old one for the date of manufacture and also on your replacement one.

 

Yea, I doubt GM is installing refurbished transmissions under warranty. It is just easier for them to install new ones. Just like they do other things that would seem like it would be more expensive. My C7 had the headliner adhesive fail. Instead of using some adhesive to reinstall it they put a new headliner in. In the future there may be refurbished DCTs available for a lower price than new and perhaps service contracts will start using them.

 

Thank you very much for that information, very helpful and encouraging...

 

Also will I have to use the 3,500 RPM limit as a "new" break in period you think? I wanna make sure it is broken in properly and not sure if that initial 500 mile period is more for the engine or tranny?

 

Nice to know those Techs are working diligently on dissecting those filters. I hope they eventually figure out what is going on. I will say it is taking some time as the 23s don’t seem much better. Wow no dipstick? Does the computer screen tell you if you are low on fluid? Or do you just wait for a CEL and have On Star lady tell you you need fluid? I bet none of you guys are looking under your c8 with a flashlight lookin for oil??

kInda like a my old girlfriend used to tell me…”My oil lights on I should probably get some oil?”

 

It's for both, but more so for the tranny and other drive train components. When you get the new tranny start the clock at zero miles.
Best of luck, I'm sure you will be fine and love the car. It's spectacular.

 

Tremec has made several changes to the DCT since the C8 first hit the streets all involving improving the things that failed. It’s well documented on this forum.

I understand this is a very frustrating problem for those who go through it but as I’ve said before these problems are in the small minority. It’s no fun being in that minority but it is what it is. If mine fails I’ll be right there alongside those who’ve had failures griping with them.

 

I think it’s a frustrating problem for all owners and perspective owner of the c8. Not just the people with immediate problems. I think it casts a dark cloud over the ownership of the car. No one has been really able to give any truly definitive information about what is going on. The people that actually have problems don’t even really know what is wrong with there own car. I am sorry but it just feels a little flakey and suspicious. Particularly after at least 3 years of this. I often examine the bottom of the car for oil. The transmission sometimes feels a bit confused- and that gets me thinking although perhaps normal for DCT. And there is that little bit of gear mesh howling at certain speeds-not bad but it’s there. Then look at Porsche trans and the clutch has its own separate oil bath. People on this forum are even speculating that the little particles may be clutch material. I think it’s time we find out…

 

I’m def losing interest in the C8. I’ll ask this, anyone on this board ever buying an out of warranty C8? Didn’t think so

 

Dont worry. Gm replaced my c8 transmission and the car runs greatnow.

the issue isnt actually the transmission mechanical parts but in my opinion a sensor programing issue.

the pcm stops communicating with the sensors in the transmission and sets a code which shuts down the transmission .

think of it this way once the transmission and pcm see the sensors go slightly outside the allowable pcm parameter (which is too tight)and thats when transmission pcm sets off the dashboard lights and the dct wont shift. (Like a limp mode to keep the lawyers happy)

in my opinion the mechanical aspect of the transmission itself is fine and its the pcm reading slightly larger parameters that tell the cars pcm that the transmission Might be in gear or in neutral are too tight and once the pcm sees that its puts the transmission in something like a limp mode setting off the code. We are talking a sensor reading thats like .008 mms too far out of range. If I took a guess the clutch pack material before the 7500 mile service is allowing clutch material on or in sensor to accumulate and its setting the code. Eight one hundredths of a millimeter,

down the road the techs will have the ability to open and then successfuly close the transmission. Change that sensor on site. Right now gm wants all transmissions back so they can examine the occurance Im discussing.

just my opinion at 19k miles and the car is running fine for the past 4k.

hope this helps. Dont worry everything will be fine.
tt