that_one_c8

Hey Fam!

It seems like I have the updated Die case for the transmission which does not require the addition of the two quarts of fluid for track days. The redesign of the case was in production vin #37263 I'm vin #38701.

The dealer I work with install the two extra quarts for track.

Should I be worried that the two extra quarts are in there when not needed, will it damage anything? Thoughts?

Thanks

C8 Corvette Stingray Transmission Gets Case Design Update (gmauthority.com)

ArizonaZ06

Doesn't make any sense. How would this happen?

A dealer would not add an additional 2 DCT quarts to any C8 unless instructed. Never heard of this ever happening?

that_one_c8

Per the manual it states the stingray needs 2 extra DCT quarts for track duty, There has been a revision to the transmission case, GM says the updated case does not need the extra 2 quarts. Dealer did not check if I had the updated case.

Andybump

OK. So you have a late 2023 model that has the later die 3 design right. And your Owner Manual and the 2023 Track Prep guide says add two quarts right? But the 2024 manual says its not required.

As far as I know, there has been no attempt to contact owners of the late 2023 models with the die 3 update, and apparently no bulletin posted telling dealers anything about it. Given that, I would hope that the extra two liters would not be harmful. It it was, I would expect GM to have made an effort to notify dealers to check that, and also telling owners about it.

ArizonaZ06

Bottom line this is not good, with the new die your DCT is 2 quarts overfilled.

For sure asap have a your dealer drain 2 DTC quarts, it should be on their dime.

RKCRLR

The 2 additional quarts isn't necessary with the die 3 case but it shouldn't hurt anything. Your dealer followed the manual. GM should have sent out a service bulletin for late 2023 vehicles stating that the the extra 2 quarts isn't necessary but they didn't as far as I know. And, in fact, it could be argued if there is no documentation stating that the extra 2 quarts shouldn't be added for your vehicle you would be in violation if of your warranty requirements if you didn't (although I highly doubt they would try to do that). It defies logic but so do some of the other maintenance requirements.

BandDirector

…gonna throw a minor wrench in here…I’m not sure if it was Conti, or who reported it recently, but the reason the 2 extra liters of fluid aren’t needed is because it’s now already been added at the factory. It’s *possible* you may be adding 2 more liters on top of the 2 more liters GM added in the C8’s with the case update that was done in late ‘23 and all ‘24’s…

I’ll see if I can find that source to confirm…

Andybump

Yes, that is my thinking about this. I'm trying to picture what I would actually do. I don't track, and dont do the 2 liter overfill on my 2021, so its academic for me. But I think in absence of any special instructions released by GM for the those late 2023 models with the die 3 transmission, I would probably go by the 2023 manual and track prep guide. The only GM notice appears to be in the 2024 manual. As far as I know, they did not update the 2023 manual for those cars that received the new transmission.

We also do not know exactly what was done to the die 3 transmission to make the 2 liters unnecessary. I think we know by now that they do not come with extra fluid - they take the same level fill as before right? So, there have been posts saying they changed the pan baffles - which I think is true - but have not see an image of the pan. But we also know they change the case - ehy actually say that in a press release. And we can see the pan bolt pattern is different so we know the case is different. Were there also case change - baffles? - that help? In any case, if it was harmful to put 2 extra liters into the late 2023 models with the die 3 transmission case, one would hope that GM would address that.

In previous model years, the only issues ever cited with the overfill were 1) maybe a slight reduction in fuel economy, and 2) a single issue of sustained high speed driving that led to a sensor being sprayed with hot fluid, in 6th gear, resulting in an erroneous over heat conditions that triggered a protective speed reduction (but still very fast). And we know that for the previous model years the manual specifically says the track fill does not have to be removed for street use (including the 2023 manuals).

BandDirector

Found it! Around the 8:20-9:30 mark, Conti says he asked an engineer while he was at eRay training about the extra 2 liters in the redesigned transmission and a GM engineer stated it’s not necessary because it’s now already in there…this is unconfirmed by GM still, but it’s enough to make me hold off adding 2 liters to my ‘24…

Andybump

Your 2024 manual already says the 2 extra liters is not needed. I'm glad the video and their answer is consistent with the 2024 manual. The question is really what about the late 2023 models with the later die 3 transmission? For those, the manual still says add 2 liters. We get that common sense says it should not be needed there either, if one is sure that they have a die 3 transmission. But the owners of those late 2023 models were not notified, and dealers apparently received no bulletin instructing them to check for that. So - if someone follows the manual and adds the two liters is that ok? And, if someone who has confirmed that they have the later model die 3 transmission in a 2023 model, is it ok to not add the 2 liters for tracking. Again, I get that common sense says that it is, but there was no notice from GM about that for 2023 owners.

RKCRLR

Conti is quite often wrong about things. I've also seen it posted that people have asked and were told that it was just the redesign that made the track fill unnecessary.
The way to confirm is for someone to post the DCT fill capacity from a 2024 service manual and compare it to an earlier service manual (that number has been posted several times). It may be slightly different but my guess is it is nowhere close to 2 quarts.
You could also compare the location of the fill plug to see if it was raised.
Or if someone has already done a fluid change on a die 3 DCT they could chime in with how many quarts it took.

Andybump

Here is Josh Holder's statement about that:
" The +2L fill was intended for “track” use as in “closed road course tracks” with sustained high G loading..........For the Z06 and all Corvettes built after July of 2023. The case and lube system have been revised so that the extra 2L of oil is no longer required for any situation."

While its been confirmed that the new case does not require the exts no GM statement that says it already has two extra liter. It is much, much more likely that the case and lube system redesign that Josh mentions were to better control the transmission fluid during the sustained high G loading, making the overfill unnecessary.

that_one_c8

Thanks for all the information, I’m going to call the dealer tomorrow morning and figure this thing out,

My take, if not required for the die3 case to have extra 2 qt’s my transmission is two qt’s over full and needs to be addressed. Nothing good comes out of overfilled anything. No fault on dealer they maybe did not know, shame on gm for not providing a tsb that states this.

I can confirm that SI GM states the 2023 fill is 12.05 qt’s with the option for track fill of 2.11. The 2024 fill is 12.05 with no option of track fill.

Thanks again guys!

Kracka

Luckily it's easy to drain back to the correct fill level. They just need to pull the fill plug and let it drain out.

Me personally though? I'd leave it in there.
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winders

Conti is WRONG as usual....he and Chuck make more mistakes than they should....

Red Mist Rulz

Complete wrong, which isn't surprising from Conti. GM has said it doesn't need the extra fluid because the design of the case and oil pickup has been changed to ensure the pump can't suck air even under the rare condition under which it could happen in the original design. The standard fill for the new DCT is still 11.5 liters. (12.05 quarts)

Red Mist Rulz

GM is terrible at communicating, but it's also true that most dealers don't even try to keep up with GM's TSBs. We don't know that GM didn't provide this information. All we know is this dealer didn't know the right answer.

winders

...and Conti finds out he was wrong at the Bash while talking to Josh Holder (go to 10:27):

MarkMeHopeful

^^^ Not surprising!

BandDirector

…I was glad he posted the update though…at least we now know what was done with the case modifications for ‘24 and why…