At least as definitive as anything from GM. From a video with Tadge, Harlan and Josh Holder


They say that they attempted to align the DCT filter intervals with other service intervals. They also said that the 2nd DCT filter change is at 22,500 miles, and then every 22,500 miles thereafter so the intervals are progressively increasing implying that the 2nd DCT filter change is 15,000 miles after the first DCT filter change.

 

Seemed pretty obvious from day one.

 

This also implies that either the DCT break-in isn't complete at 7500 miles or that the technical requirement for the 2nd filter change is actually 22,500 miles but they moved it in to align with other services. It will be interesting to see if the 2023 DCT filter monitor shows that the 2nd filter change needs to occur 15,000 miles or 22,500 miles after it was reset.

 

Yep, so I'm all clear on the second change of DCT filter at 22,500, OR 3 years which ever comes first ( according to the 2020 manual). It also shows changing the DCT Fluid at 3 years.

So my 2020 will be 3 years old this August. I'm at 11k miles now, and just for grins decided to check and see what the maintenance minder showed. It showed my engine oil / filter at 26% which would make sense, however the DCT showed at was still at 86% life left. I figured that it would also go by time and mileage.

I'm still going to do both DCT filter, as well as DCT fluid change at 3 years regardless of how many miles I have on it, but I would guess it will be about 14k or so.

 

There is no 3 year time requirement on the DCT filter nor is there a requirement to change it when the DCT fluid is changed. And you are correct that the DCT fluid life monitor doesn't appear to track time, it is up to us to keep track of the 3 years.

 

There were a number of people who interpreted GM's language as meaning 22,500 miles AFTER the 7500 miles service. And GM's wording was unclear enough to support that interpretation.

 

RKCRLR is correct, there is no time based filter change requirement. The OM only says that IF the filter change is due soon when you change the fluid, go ahead and change it. And the reverse: If the oil change interval is due soon when you're changing the filter, go ahead and change both.

 

^^^ Yes, my error regarding the no time based filter change requirement.

So, if you were me, this August, would you at 3 years old JUST change the DCT fluid and leave the existing DCT filter ? As I mentioned above, I'll likely only have 14k miles by then. It would probably be 18 months to 2 years beyond this Aug before I get to 22,500.

I did have the initial 7500 mile DCT filter and flush done ( at 6k miles) at 1 year old.

 

I plan to treat them separately since I can do the fluid changes myself but don't have the scan tool to perform the DCT hydraulic system flush prior to removing the filter, plus the filter isn't cheap at over $100. But if they're close I'll do them both at the same time. Technically, you should get your filter changed again at 21,000 since you only had 6000 miles on your car when you had it changed the first time.

 

^^^ Agreed on the 21,000 mile next time DCT filter...... 6 + 15.

That makes sense..... keep them as separate entities. It's just so off to me not to change a filter when you change the fluid...... hard to teach an old dog new tricks.

 

So....

Given the issues a small percentage of owners are having with the DCT, I would be very tempted to go ahead and change the filter at the same time. It can't hurt anything but your wallet. They're going to be under the car with the shear plate removed, so the extra labor involved in replacing the filter should be minimal. (Hopefully they won't charge the same amount of labor if they were doing just the filter - ask them about that.) But if you do that, you should probably change it again at 22.500, since that seems to be when GM thinks it's safe to extend the interval.*

But I don't think there's really any need to change it until you get close to the 22,500 miles.

*Or maybe they just want to keep it in sync with the ~ 7500 mile oil change intervals. But the OLM never lets me go 7500 miles anyway. I guess I'm too aggressive. I'll probably hit 22,500 miles pretty close to the 3 year interval, so I'll just do both of them at the same time. Or, more accurately, let the dealer do both of them.

Oh, one more thing: Get all that carbon fiber out of the garage and DRIVE it more often!!!

 

Good thought. If I weren't so lazy, I'd change the fluid myself, too.

I know the feeling. But I figure the 6 - 8 oz of dirty fluid left in the filter is a tiny fraction of the 12 (or 14) quarts in the DCT sump.

 

I think I saw a comment that there were still a couple of quarts left in the transmission when the track guys do oil changes so that 6 - 8 oz is even less significant in the big picture.

 

My 2020 Owner’s Manual has the following grid. Seems pretty straightforward to me.

 

Footnote 5 also says:
"The initial transmission canister filter change must be performed at 12 000 km (7,500 mi), and every 36 000 km (22,500 mi) thereafter."
If I changed my filter at an odometer reading of 7500 miles and 30,000 miles I would be compliant with footnote 5.

 

I'll be following the Owner's Manual too.

That way there's never a question when it comes to any warranty claims.

 

In your case (2023) they have done away with the service schedule and just have text direction. With regards to the DCT filter change the manual says to change the filter when the monitor (which 20201-2022s don't have). So it will be interesting if the monitor says to perform the 2nd filter change at 22,500 odometer miles or 30,000 odometer miles (assuming you perform the first change at 7500 miles and your dealer resets the monitor).

In my case there is a conflict in the manual, do I get to choose which part of the conflicting statements to comply with?

 

I do my own oil changes. I plan on changing the DCT filter with every engine oil change and maybe slack off after a while to every other engine oil change. If the DCT was proven bulletproof, I probably would not change as frequently. And it is really easy for me to do, so why not?

 

From the 2023 Corvette Owner's Manual page 304
JT

 

I listened to it - and I agree. I think it is very, very clear. They aligned the first service interval at 7500 miles - for DCT filter and engine oil/filter changes. The second DCT filter change, clearly stated in this video, is at 22500 miles on the odometer. The third is and subsequent changes are every 22500 miles apart. All of this is between 19:16 and 19.31.

They also said they attempted to be very clear in the manual about that. I have to say in that area, they are less clear. The tables in the 2020-2022 manuals showing service at 7500 miles and 22500 miles would have been clear, except the footnote muddies it a bit - the footnote could have been easily clarified. Instead, for 2023 they eliminated the tables that show service at specific odometer readings, and also include verbiage that is similar to the footnote in previous manuals - sounding like its "every 22500" miles after the last change. I have always planned to have mine changed at 7500 and then at 22500 on the odometer, even though I can see the lack of clarity in the manuals.

I agree also that since the intervals get progressively longer (also very clearly stated in the video), with the second interval being only 15000 miles, it suggests that break-in for the transmission is not fully complete at 7500 miles (at least that is one explanation for it). Some have suggested that the accumulation of break-in debris is actually over much earlier in the 7500 mile period, but if the break-in is really continuing after 7500 miles, it really drives home the need to change it at 7500 miles even if changed prior to that. Or, perhaps they are just being very cautious.

They have been pretty consistent about changing at 7500 miles.