Can you provide a link to the proof of the metallic/clutch buildup in the DCT? And explain how the vast majority of C8 owners that follow the maintenance schedule don't have DCT problems?

 

I do all my own preventative maintenance on my other cars (Honda pilot and ridgeline with the 3.5 V6) and will do the same on the corvette. I change the oil, transmission, transaxle, rear end fluids on my own schedule, which is much earlier than recommended. Been that way for many many years and had great success with minimal drivetrain issues. I dont know much about the DCT, but I do know that I will be hyper vigilant in changing the filter and fluid way early. I have always used OEM transmission fluid in my honda's. The comment on Valvoline has me curious...why use a non OEM trans oil...is it purely a money concern or a product quality issue? Any input is appreciated.

 

Only in your mind, which insists a manufacturing error is somehow related to the oil used.

 

Can't wait to see the answer to this one.

So many many people on this forum claim absolute knowledge of things they never have seen and never will see, and have no actual information about. And it seems the less information that's available (like what's going on inside the DCT none of us have ever seen), the more certain they are of their own "knowledge."

 

And for many years I've followed manufacturer maintenance schedules pretty much to the letter, and have had no drivetrain issues on any of my cars or motorcycles. Just sayin'.

Well, I'll take that back. A Toyota minivan with well over 100,000 miles that both of my sons abused while in high school did start to show some slippage in the transmission. Otherwise, I can't remember having a single drivetrain issue since I started driving 55 years ago.

 

Understood. Man you've got me beat, I have only been driving 50 years.. lol.

 

Sure - we've been discussing it in another thread. See attached TSB.

I live 45 minutes from Road America in Wisconsin. There’s usually more than one C8 up there most weekends with DCT problems. Picked up a lot of tips over the years from the track rats…..passed some along here. The “vast majority” of car guys I know spend minimal time on forums and most of the time in the real world. A proverb taught in Engineering is “Absence of evidence is not necessarily evidence of absence"

DCT Conversion Die 1/2/3

Here is a pic of an old magnetic drain plug I rolled around in the DCT oil I drained from my previous 2024 3LT-Z51 earlier in this thread…..the magnet is very strong. This was @ 2,500 miles and consistent with a dozen other C8 DCT’s I’ve seen that run @ RA. I cut apart the filter, and it also looked nasty and had plenty of sparkles in it. ERay just rolled past 1,500 miles, so I’ll be doing the initial DCT service this next weekend and also installing a magnetic drain plug.

 

Not sure he’s been driving that long Rich. His profile says born in 1992, which explains his constant yapping.

 

thats ok...we all have our own ideas/opinions. I will continue my "over care" and do what ever I can to all my cars so they are well taken care of. This is my first corvette and my 1st mid engine car...my quickjack has been fit tested and is perfect...already installed billet pucks. For this thread, still interested if others have used the Foxwell 510 elite for a 2025 trans flush. One pers9n responded affirmative, wonder if anyone else.

 

Every word you posted is false and an ignorant assumption. I’ve spent my life in propulsion engineering including a MSME from Purdue, GM Engineering, an Indy Car team, and GE Aerospace. Yes, many people talk out of their *** on here, I'm not one of them, nor are you anyone to judge who is. My post count is low because I forget that on the internet everyone is an “expert". Anytime an in-depth topic comes up, all the Dunning Kruger’s and their furious typing are on full display.

Contrary to your assertions, I’ve seen at least a dozen C8 cradles dropped at the paddock’s and shops around Road America and IRP with guys managing all sorts of tuning and DCT clutch/half-shaft/shifting issues on modified road and drag cars. I’ve seen valve body and solenoid replacements, complete TR-9080 teardowns after something broke (no warranty), the helical cut gear lash/wear patterns on the internal gears, Tremec factory mis-alignment and half-assed QC, guys polishing the shift forks, pivots, and saddles for faster shifting on power, various sludge, burnt clutches, debris, and sediment along with most seal replacements.

I also have colleagues still @ GM Engineering in senior mgmt roles. "knowledge of things they never have seen and never will see, and have no actual information about”? - your talking to the wrong guy.

 

You cannot “Over Care” cars of these capabilities…..being dilligent doesn’t hurt anything.

I have a Launch CReader Elite that works perfectly on 2023-later C8’s including my 2025 ERay and both of my McLaren's…..$150 on Amazon….DCT flush/leak test, steering sensor relearn after alignment, etc…..all works A-OK. I also just bought a TOPDON J2534 interface and subscriptions to Delco TDS to do the necessary software updates and recalls…..works perfectly with identical capabilities as a Chevy dealer.

 

The bulletin, which refers to the park lock sensor drift issue, shows that after a certain date, the bulletin does not apply. The die 3 change was introduced in late 2023 and all 2024 Stingrays. It would take a little more checking to confirm that the cutoff does coincide with the die 3 change. But would suggest that there is a change that may prevent the issue called park lock sensor drift.

The name tends to imply that this has something to do with actual unintended motion of the sensor or a communication error - and I think some posters even said that - nothing in the bulletin mentions anything about accumulation of metal particles on on the sensor, or the placement of shield to prevent that. As far as I know, the only source for that additional information was a technician that talks with the factory a lot and asks lots of question. I did not dispute that, and am not now disputing it. But it would be more interesting if we could see an image of that sensor and the shield that was added or a GM document discussing it.

Regardless of what factors contribute to the park lock sensor drift that is discussed by the bulletin, the cutoff date for the application of the bulletin tends to imply that change was made affecting the issue in the bulletin. If it does coincide with the date when the die 3 transmission was introduced in the 2023 models, it would strongly suggest that the change was included with the die 3 changes. And if that is true, it also seems to be at odds with GMs statements about it that said the alterations are unrelated to the reliability or durability of the transmission. It has been touted as primarily being a change to the case and pan to eliminate the need for the track fill, and a change to the cooling system - with very little other detail publicly shared.

I'm not surprised that there are metals in the fluid, but I am surprised (or disappointed) that the filter does not remove them - so that they ostensibly accumulate over time in the fluid. There are magnets in the pan that one could remove and inspect. And we have seen images of the filter housing covers with debris on it - don't know if it was ferrous metal or not.

 

Generally speaking, most good oil analysis methods will detect particles below 10 microns. This is well below the average micron rating of most oil filters. The point is - iron shown to be present in my DCT fluid will remain suspended in the oil until I drain it from the unit. In the meantime, it will be attracted to and build up on anything that is magnetic - just as it will on a magnet in the oil pan or on a magnetic drain plug. If components in the transmission are susceptible to failure from ferrous contamination, then there exists a built in failure that no filter can avert. In the case of the park pawl sensor, if a baffle can divert oil splash away from this sensor, that should increase it's longevity. A better solution would be to make components/sensors internal to the trans impervious to contamination from wear elements in the oil.

 

Iron (Fe) 22 ppm @ 6,433 miles, 1 external filter changed, before the service. Just looked up the trans fluid analysis report. Anyone else?

 

2365 miles. Filter changed once previously at 550 miles.

 

We know there are magnets in the pan, How does that factor in? I asked the company that also does my engine oil, about the filtermag units on my oil filter. He told me that was the first time anyone asked that question. His guess was the filter would have caught anything bigger than the 30 microns anyway. The outlines on the filter can was the consistency of Anti seize, and about that messy to get off your fingers. The outlines on the first 5 filter cans were very similar. Yes 5 engine oil changes in 7,653 miles.

 

Thanks for the UOA. I forgot to ask on the other thread……is the assumption that the wear metals in your UOA would become excessive if the GM 45K mile OCI was used?

 

Thats a-ok for my 2025 ERay, but there are 120,000+ MY2020-MY2023 C8’s out there the bulletin does apply to. GM’s vague language aside, three consecutive flush procedures (and in some cases more) to resolve DTC’s indicates a debris problem. Doesn’t matter the lawyers won’t allow it to be said directly.

 

Please give details of your filtermags. Where do you use them?

 

In short - yes. Way before 45K miles.

The TR-9080 has proven to be susceptible to fluid contamination. In addition, the oil filter is too small and bypasses too easily. I perform all the routine maintenance on my car and it is all too easy for me to change the fluid and DCT filters, so why wouldn't I?

Next oil sample I send out will include a particle count which will give a more complete picture of what I'm looking at.

The concern is wear metals and nonmetallic debris coming from the both the input clutch assemblies and the eLSD clutch packs.