Here is a tech link from July of this year that appears to summarize (and reiterate) most everything that has been said about DCT service. Its not (in my view) new info, but it does put it all together.

https://gm-techlink.com/?p=18768

Notable points:
It reiterates the need to change that filter at the recommended mileages (that not limited to just the first 7,500 miles): "It is recommended to only replace the canister filter at the required maintenance interval due to the loading characteristics of the filter. (Fig. 6) The filter does not need to be changed earlier than 7,500 miles (12,000 km)."

It still includes what I consider a discrepancy about the window around the service intervals - its says +/-1000 should not be detrimental, but then it also includes the specific +/- 500 miles. It also is specific about the second change being at 22,500 miles on the odometer, then every 22,500 miles after - even though the actual wording seems to say every 22,500 miles after the first change. It discusses a little about the filter life monitor. It discusses the transmissions that do, and do not require the track fill.

And it discusses the transmission fluid. It specifically says Delco DCTF FFL-4. Unlike motor oil requirements, the statement "or equivalent" or "meeting the requirements of ..." are not there. The owners manual says see the dealer (still even in the 2025 manual). Early service manuals say Pentosin EG FFL-4 and Fuch Titan EG FFL-4. Nothing about specifications or equivalent. But Delco DCTF FFL-4 is also mentioned in this early tech link released in March 2020, introducing the then-new C8 to the techs.

https://gm-techlink.com/?p=12881

I have not seen a service manual version that has been updated to say Delco DCTF FF-4 (instead of Fuchs Titan) but it may have been updated. I'm not saying that using a different brand is a problem - and I am aware that there are supposed to be laws that a manufacturer cannot require use of a specific brand as a condition for a warranty claim, so long as the product did not cause the issue. I'm just pointing out how its stated in the relevant documents (owners manual, service manual, and tech-link).

 

The 'loading' of the filter comment is interesting. A used, but within designated limits, oil filter does a better filtering job due to loading too .... often discussed on the 'Bob/oil guy' site.
IOW, early and often changes may be counterproductive in the filtering event. (my assumption based upon that info)

 

I like this statement:
"The canister filter (Fig. 5) should be replaced in the first 7,500 miles (12,000 km) due to the initial break-in of the internal transmission components. The 7,500-mile (12,000 km) break-in period is when most contaminants may be created," and this one "The vehicle should be driven like the initial new vehicle break-in period for at least 1,500 (2,400 km) to protect from damaging the differential gear surfaces." This pretty much confirms that the new vehicle break in is as much about the transmission as it is the engine. And seem to say its about the differential gear surfaces. And it seems to confirm what we assume - the most contaminants are produced in the first 7,500 miles. But the statement that the second change is at 22,500 miles (and not 22,500 miles from the first change) seems to also suggest that additional debris contamination continues into the next filter service interval. All not new info, but its just doubling down on things that have been said before.

 

It will be interesting to see if the DCT filter life monitor turns out to be consistent with the second DCT filter change at 22,500 miles on the odometer. So far the data is leaning towards it being 22,500 miles after the first change. If the requirement really is 22,500 miles on the odometer for the second change but the DCT filter life monitor isn't programed to reflect that GM should issue a TSB since and notify owners since there isn't anything in the owner's manual for cars with a DCT filter life monitor that says the second DCT filter change is at 22,500 miles on the odometer (at least that I'm aware of).

 

Most new filters that rely on a media are worse at filtering fine particles than ones that are partially loaded. You can picture the passages getting smaller and more torturous as the filter becomes more loaded at the expense of higher pressure drop. That is until the filter fails structurally or the bypass opens. Or it stops the passage of air/fluid.

 

Yes. I assume you picked up on this statement:
"Beginning with the 2023 model year, the Corvette has a maintenance minder on the Driver Information Center that will display a maintenance message shortly before the 7,500-mile (12,000-km) maintenance interval. (Fig. 8) The message also will appear every 22,500 miles (36,000 km). The transmission filter minder cannot be reset like the engine oil life monitor.'
that sounds like after the first reset, it just reverts to every 22,500 miles.

As noted the wording at the beginning of the tech link article says at 22,500 for the second one, which we have also heard verbally from GM reps. I'm in the camp that thinks (or hopes) that tech link articles are mostly right - but they do sometimes contain differences (such as the +/- 1000 miles) with respect to what I think are more "official" documents (that is the Owners Manual and the Service Manual). The 2024 tech link article still references the tabular form of the maintenance schedule, even though it was deleted from the later owners manuals. I do not know if one could cite a tech link as the basis for a maintenance schedule if it differs from the service manual or the owners manual.

 

I'm now leaning more towards the requirement for the second filter change being 22,500 miles after the first change and not 22,500 miles on the odometer which is consistent with the 2023 and later owner's manual. And even though the earlier manuals have the table showing the second DCT filter change at 22,500 miles they have a footnote 5 that states "The initial transmission canister filter change must be performed at 12 000 km (7,500 mi),a nd every 36 000 km (22,500 mi) thereafter." The TechLink article shows the table referencing footnote 5 but doesn't include the footnote.

The TechLink article only states "After the initial service, the canister filter should be changed at 22,500 miles (36,000 km) and then at regular 22,500-mile (36,000-km) intervals." once however it states "Beginning with the 2023 model year, the Corvette has a maintenance minder on the Driver Information Center that will display a maintenance message shortly before the 7,500-mile (12,000-km) maintenance interval. (Fig. 8) The message also will appear every 22,500 miles (36,000 km)." and "The initial transmission canister fluid change must be performed at 7,500 miles (12,000 km), and every 22,500 miles (36,000 km) thereafter." So just going by the number of times it is written the requirement every 22,500 miles after the first time it is changed wins.

And there is even more implications that the DCT is fully broken in after 7,500 miles in the tech article.

 

Life and Corvette "living" is sure difficult over here... Has me asking do I need this?

 

A oil filter is like a steak. A steak is best the day before it spoils, A oil filter, filters best the day before it stops up.

 

I have a 2023 and have read many times that the trans filter monitor can't be reset. Does that mean owners can't reset it? When the dealer performs your 7,500 mile service and change the filter, do they reset it?

 

It can be reset by the owner however when it is reset it will show the next change due in 22,500 miles. So if you reset it before 7,500 miles you can't make it show you are due again in 7,500 miles.

 

It's confusing, but it can be reset from the dash, by the owner and by the dealer.

But, in the event that the transmission replacement, it can't be reset so that it will indicate the next change a 7,500 miles - so the owner must observe that.

And there may be one other thing. I think the Oil Life System function resides in the ECM. I believe I have read, in the service manual, that when the ECM is replaced, the remaining oil life can be recorded, and then it can be re-entered in the new module. If I can find that later, I will post it. But probably that cannot be done with the Filter Life System - I am not sure - that is speculation.

Found it -

 

I just had my trans filter changed 2 days ago, the dealer also did my oil/filter too.
when I got in the car (24SR) the " change transmission filter" warning was still on the dash(wtf). The engine oil minder was reset, but not the filter minder. I was about to go back in to the service desk, but I went through the menu and reset the trans filter life myself, so the comment in the tech doc may only be applicable to 2023.

 

It can be reset in 2023 and 2024 and 2025. I think it means what was said in posts 11 and 12 - keep it mind that statement is in a document for tech (dated July 2024), and I think means it cant be reset the way the tech can reset the oil life monitor by re-entering the remaining filter life. Here is from the 2023, 2024, and 2025. And, if it is reset accidentally prior to the 7,500 miles, it will not tell you again that you need to change it at 7,500 miles.

2023":The Transmission Filter Life display must be
reset after each filter replacement. It will
not reset itself. Do not reset the
Transmission Filter Life display accidentally
at any time other than when the filter has
just been replaced. It cannot be reset
accurately until the next filter change. To
reset, see Dual Clutch Transmission Fluid Life
System."

2024:"The Transmission Filter Life display must be
reset after each filter replacement. It will
not reset itself. Do not reset the
Transmission Filter Life display accidentally
at any time other than when the filter has
just been replaced. It cannot be reset
accurately until the next filter change. To
reset, see Dual Clutch Transmission Fluid Life
System."

2025:"The Transmission Filter Life display must be
reset after each filter replacement. It will not
reset itself. Do not reset the Transmission Filter
Life display accidentally at any time other than
when the filter has just been replaced. It cannot be
reset accurately until the next filter change.
To reset, see Dual Clutch Transmission Fluid Life
System"

And, the instructions to reset it are the same in all three.

"How to Reset the Dual Clutch
Transmission Fluid and Filter Life System
Reset the respective system whenever the
transmission fluid or external canister filter
is replaced so that the system can calculate
the next service interval.
To reset:
1. Place the vehicle in P (Park).
2. Select Transmission Fluid Life or
Transmission Oil Filter Life on the DIC
menu. See Driver Information Center
(DIC) 0 93.
3. Press the thumbwheel to move to the
Reset submenu. Select Reset
Transmission Fluid or Reset Transmission
Oil Filter. A confirmation page will be
displayed, press the thumbwheel again
to confirm the reset.
4. When the Transmission Fluid/Filter Life
System is successfully reset, 100%
remaining life will be displayed."

 

GM never (or pretty much never) uses TSBs to notify owners. TSBs are sent to dealers, not owners. So if the DCT filter monitor tells the owner the they're good to 36,000 miles, and they don't see a dealer during that time, they'll never know.

Just as GM never notified owners of the 7500 +/- 500 mile requirement until the 2024 owner's manual.

And it won't surprise me at all if the filter life monitor doesn't match the written guidance in GM's TSB. GM probably provided the same ambiguous language that's in the OM to the software team. Heck, in 5 years of production GM hasn't fixed the failure of the DCT oil life monitor to reflect the 3 year requirement. GM has some great engineering, and a lot of lousy processes.

 

But the bolded statement directly contradicts what Tadge and Josh Harlan said, and what Criswell's service department told me. I think the issue is that GM couldn't write clear, concise English if the company's survival depended on it, and continues to use the same ambiguous language that first appeared in the 2020 owner's manual. The fact that the ambiguous language has resulted in the same possible error being repeated in multiple locations doesn't prove anything. Heck, I've managed tech writers, and by now GM's tech writers are probably just copying each other, and likely no one of has ever gone back to engineering to ask for clarification. Even if your interpretation is right, I think that changing the fluid 7500 miles earlier than necessary isn't going to hurt anything. OTOH, changing it 7500 miles too late might.

 

I agree the TSBs aren't used to notify owners of problems. But if the DCT filter life monitor was programmed incorrectly then a TSB should be issued to notify dealers of the issue. And if following the maintenance instructions in the owner's manual could put the drivetrain (and/or warranty) in jeopardy then GM should send a notice to the owners.

The problem with relying on dealers to clarify the maintenance requirements is that they often don't do it correctly, just look at all of the posts from people that have been told something that is in conflict with the actual requirements.

 

That I agree with. Unfortunately, GM seems to have no interest in contacting owners directly about these kinds of things, nor in making sure dealers actually read and follow TSBs. I like my car. I think GM as a company pretty much sucks, especially when it comes to customer service.

 

GM (or whoever is responsible or TechLink articles) had the perfect opportunity to clarify the requirements when they updated the article and they failed. And if I did all the maintenance the couldn't hurt I could easily exceed the maintenance costs of a Ferrari.

 

Tho it is complex I think it can be made simple ...

Change at 7500 or thereabouts. Change again at 22,500. .. Change at 45,000... 67,500.. .etc.

Of course change when replacing the fluid, every three years or at 45,000 whichever comes first. ...

If the filter has been changed because the fluid has been replaced earlier than the mileage specification due to the passage of time, .. STILL change at the SPECIFIED mile marks. ..

Doing this will be sure to keep your warranty in effect. It will probably mean that the filter is being changed "early", but so what... more important to keep the warranty than to save a few $$$ on filters.