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That kind of thinking is why people changed before the 7500 in the manual and the second time after the 7000-8000 window which is out of the GM requirement now published. Personally I think doing a little more maintenance is okay and even if the OP has a problem GM should cover it. If they didn't I'm pretty sure arbitration would side with me.
Yes. The letter covers several "exceptions". If you change it early change again before 8000 miles. If you have over 8000 miles and have not changed the filter, then make an appointment with your dealer (presumably to change the filter ASAP). It does not explicitly cover the case of if you did it early and then did not do it before 8000, but in my opinion, the intent is just to change it ASAP after receiving the letter. Its what I would do.
Technically, it should not be harmful to go further. But it avoids any risk however small it may be.
^^^^
Andy this is a post you made August 21, 2023 BEFORE THE GM LETTER:
Quoting: Here it is - it is just the first page showing date and the info about when it needs to be done. Someone else found and posted it on the forum - I saved it from that post.
And I agree - completely incorrect that GM wont pay for it after 7500 miles. But you really want to avoid that situation anyway if possible.
PS: I was aware of the Published +/-500 before I had my 2nd DCT filter change August 8, 2023 with ~8000 miles. DID NOT NEED A LETTER WRITTEN IN 2024!
Found another Post where a Member refers to his prior post at a race where he asked a GM Exec the tolerance was on the 7500 filter charge. He was told +/- 500 miles which later was found in printPOST by Member bhvrdr August 22, 2022
He was referring to his early post that i recall was at a Race where Corvettes participated, quoting: "Add to that, what an engineer says at an event is not necessarily going to hold up in court. You certainly hope they give accurate information but anyone can misspeak."
^^^^
Andy this is a post you made August 21, 2023 BEFORE THE GM LETTER:
Quoting: Here it is - it is just the first page showing date and the info about when it needs to be done. Someone else found and posted it on the forum - I saved it from that post.
And I agree - completely incorrect that GM wont pay for it after 7500 miles. But you really want to avoid that situation anyway if possible.
PS: I was aware of the Published +/-500 before I had my 2nd DCT filter change August 8, 2023 with ~8000 miles. DID NOT NEED A LETTER WRITTEN IN 2024!
Yes - it appears that the tolerance around the 7,500 appeared in the Service Manual before the letter came out. But that info was not shared with owners until it appeared in the letter and the 2024 manuals. So many owners of 2020-2023 did not receive the clarification until it was too late.
There has been lengthy discussion of how "clear" it was in the earlier manuals - all about the definition of "at". Did "at" 7,500 mile mean as close as possible to 7,500 or did mean on or before 7,500 miles. Many say its clear. But many others, used to other maintenance requirements (for many years) interpreted it to mean "at least as often as...". And even if one did understand that it meant "close to ..." , how close is close? Dealers did not know either. Over the years we have heard verbal statements that said something like "if you change it at 3000, you need to change it again at 7,500" from GM reps. And many have reported varying advice from dealers 1000 or 1500 is close enough. I think @RKCRLR was told that 4500 was good enough. And there was even a techlink article that told the techs that +/- 1000 "should not be detrimental". Go figure. That same tech link article even included the official statement of 7,500 +/-500.
We have to guess/hope that those that changed it earlier, in good faith, but missed the window, and changed it again as soon as they received the notification, will not have an issue if they have a transmission issue. Common sense (I hate that term) tells us that if you change it early, you could go at least another 7,500 miles without filling up the filter (assuming GMs original requirement is sufficient in the first place - some don't think so). I do think if its changed early, there would be a risk if you go all the way to 22,500. And thats the issue. If you changed it at 4500 miles, is it safe to go to 22,500? How about 4500+15000= 19500? I did a little math assuming a linear taper (not exponential) to the generation rate of break-in debris over the first 7,500 miles, and my guess (entirely based on assumptions) is if changed at 4500 you could safely go to 16500 miles. And thats very conservative in my opinion. But who knows what GM will think?
Makin' more stuff up - keep in mind that many owners wait til 1500 miles before they do a launch control and get real aggressive with the throttle. So there could be a burst of break in debris that starts at that point,
^^^^
Agree the +/-500 miles grace period was not in my 2020 Owner's Manual BUT I knew well before I had my 2nd DCT filter installed in August 2023 it was OK up to 8000 miles.
Been searching for that 1st reference which was verbal BUT have not found.
What I did find was this post by the member who reported the +/-500 mile as a verbal comment from a GM person at a race:
This POST by Member bhvrdr in August 22, 2022 was a year BEFORE I had mine 2nd DCT filter changed at ~ 8000 miles a year before I had my 2nd DCT Filer chaged.
He was referring to his early post that I recall was at a Race where Corvettes participated. So his post was BEFORE 8/22/2022!
Quoting: "Add to that, what an engineer says at an event is not necessarily going to hold up in court. You certainly hope they give accurate information but anyone can misspeak."
Granted as his comment stated, a verbal comment is not a guaranty but was well before the GM Official Letter. It was in writing to dealers and should have been known. But as we know they often don't know everything GM sends in the form of Bulletins etc regarding whatever vehicle maintenance.
^^^^
Agree the +/-500 miles grace period was not in my 2020 Owner's Manual BUT I knew well before I had my 2nd DCT filter installed in August 2023 it was OK up to 8000 miles.
Been searching for that 1st reference which was verbal BUT have not found.
What I did find was this post by the member who reported the +/-500 mile as a verbal comment from a GM person at a race:
This POST by Member bhvrdr in August 22, 2022 was a year BEFORE I had mine 2nd DCT filter changed at ~ 8000 miles a year before I had my 2nd DCT Filer chaged.
He was referring to his early post that I recall was at a Race where Corvettes participated. So his post was BEFORE 8/22/2022!
Quoting: "Add to that, what an engineer says at an event is not necessarily going to hold up in court. You certainly hope they give accurate information but anyone can misspeak."
Granted as his comment stated, a verbal comment is not a guaranty but was well before the GM Official Letter. It was in writing to dealers and should have been known. But as we know they often don't know everything GM sends in the form of Bulletins etc regarding whatever vehicle maintenance.
I had my first filter change at about 6500 miles less than a year after delivery. so early 2022. I needed an oil change, and figured might as well have them both done at the same time since GM would only pay for one service. At that time, Criswell had received no information regarding the +/- 500 mile requirement. And unlike some dealers, Criswell's Corvette techs do keep up with GM's communications. So engineers may well have been saying that, but no one had communicated it to dealers.
^^^^
Agree the +/-500 miles grace period was not in my 2020 Owner's Manual BUT I knew well before I had my 2nd DCT filter installed in August 2023 it was OK up to 8000 miles.
Been searching for that 1st reference which was verbal BUT have not found.
What I did find was this post by the member who reported the +/-500 mile as a verbal comment from a GM person at a race:
This POST by Member bhvrdr in August 22, 2022 was a year BEFORE I had mine 2nd DCT filter changed at ~ 8000 miles a year before I had my 2nd DCT Filer chaged.
He was referring to his early post that I recall was at a Race where Corvettes participated. So his post was BEFORE 8/22/2022!
Quoting: "Add to that, what an engineer says at an event is not necessarily going to hold up in court. You certainly hope they give accurate information but anyone can misspeak."
Granted as his comment stated, a verbal comment is not a guaranty but was well before the GM Official Letter. It was in writing to dealers and should have been known. But as we know they often don't know everything GM sends in the form of Bulletins etc regarding whatever vehicle maintenance.
The point is that a C8 owner would not know this unless he followed the forum/social media. A majority of C8 owners don't participate in the C8 forums/social media. And, as mentioned above, dealers often provide incorrect information. My dealer (and Chevrolet Customer Service) told me I didn't need to change the DCT filter again even though I had it changed at 4,600 miles. And then the question becomes should you supercede documented requirements in the owner's because of posts you see on social media.
GM made multiple mistakes. GM should have put the current requirements in the 2020 owners manual in the first place (were they not aware of the DCT break-in requirements?). And as soon as they discovered the original manual was in error they should notified owners that the maintenance requirements changed. I certainly get enough promotional emails from GM, they could have sent out an email about the revised requirements. And they should have better control over dealers that continue to provide incorrect information.
But it was not "clear" that the requirement was if the DCT filter was changed before 7K miles that it needed to be changed again between 7K and 8K miles in earlier cars.
Its pretty clear in the owners manual of my 2023, page 304. It says to change it at 7500 miles, the way I comprehend this, if it was allowed to be changed sooner it would say so, so my assumption was it has to be changed at 7500 miles, even before the letter was sent out confirming this. Could they have made it clearer? Yes, they could have
You beat me to it. I read my owner’s manual right after I picked up my 2021 and it very clearly states the 7500 mile requirement filter change in a box marked “CAUTION.” I had my free filter change around 6000 miles and paid for it at 7100 miles.
I had my first filter change at about 6500 miles less than a year after delivery. so early 2022. I needed an oil change, and figured might as well have them both done at the same time since GM would only pay for one service. At that time, Criswell had received no information regarding the +/- 500 mile requirement. And unlike some dealers, Criswell's Corvette techs do keep up with GM's communications. So engineers may well have been saying that, but no one had communicated it to dealers.
Originally Posted by RKCRLR
The point is that a C8 owner would not know this unless he followed the forum/social media. A majority of C8 owners don't participate in the C8 forums/social media. And, as mentioned above, dealers often provide incorrect information. My dealer (and Chevrolet Customer Service) told me I didn't need to change the DCT filter again even though I had it changed at 4,600 miles. And then the question becomes should you supercede documented requirements in the owner's because of posts you see on social media.
GM made multiple mistakes. GM should have put the current requirements in the 2020 owners manual in the first place (were they not aware of the DCT break-in requirements?). And as soon as they discovered the original manual was in error they should notified owners that the maintenance requirements changed. I certainly get enough promotional emails from GM, they could have sent out an email about the revised requirements. And they should have better control over dealers that continue to provide incorrect information.
NOT arguing you both don't have a good case! Just saying when I had my 2nd DCT filter change, as my 1st was year 1 was changed year one engine oil/filter free to me with ~3000 miles, I knew then I had to do it again at 7500 miles.
And agreed a member asking a GM rep at a Race sometime prior to August 2022 (and posting +/-500 miles on the Forum) did not constitute an "officinal" GM position. BUT as I searched those long threads looking for his actual post many stated they understood the GM +/- 500 mile position by August 2023.
Heck if my warranty was denied having done a charge at ~6000 miles I would also argue. Just stating when I had mine changed in August 2023 I and the tech knew had to be done before ~8000 miles ! Sure that +/- 500 mile grace period should have been included in a footnote in the Maintenance Table of my 2020 C8!
You beat me to it. I read my owner’s manual right after I picked up my 2021 and it very clearly states the 7500 mile requirement filter change in a box marked “CAUTION.” I had my free filter change around 6000 miles and paid for it at 7100 miles.
Show me that note in my 2020 manual. And to most people using common sense that caution note would be interpreted as it is OK to change it sooner as long as you didn't exceed 7,500 miles for the next change like many people do for engine oil changes. And if you aren't going to use common sense and interpret the requirement literally the you couldn't change it before 7,499 miles or after 7501 miles.
Show me that note in my 2020 manual. And to most people using common sense that caution note would be interpreted as it is OK to change it sooner as long as you didn't exceed 7,500 miles for the next change like many people do for engine oil changes. And if you aren't going to use common sense and interpret the requirement literally the you couldn't change it before 7,499 miles or after 7501 miles.
I’m not here to argue with you. I know that you did your filter change early. You’ve posted that you have documentation to prove what you were told. I wish you the best if you ever need it. I hope not and only because I hate to see DCT failures.
I’m not here to argue with you. I know that you did your filter change early. You’ve posted that you have documentation to prove what you were told. I wish you the best if you ever need it. I hope not and only because I hate to see DCT failures.
Personally, I believe that if you changed your filter early but got to the point that you changed it again without problems that you won't have any subsequent problems associated with changing the filter early.
Personally, I believe that if you changed your filter early but got to the point that you changed it again without problems that you won't have any subsequent problems associated with changing the filter early.
It’s on page 292, #5, but you are correct that it doesn’t say +/- 500 miles.
Show me that note in my 2020 manual. And to most people using common sense that caution note would be interpreted as it is OK to change it sooner as long as you didn't exceed 7,500 miles for the next change like many people do for engine oil changes. And if you aren't going to use common sense and interpret the requirement literally the you couldn't change it before 7,499 miles or after 7501 miles.
So I agree with you. But footnote 5 in the 2020 manual does say "at 7,500 miles" like this "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." And yeah good ole common sense tells us that there must be some leeway around that. But what is it? Is it two sided or must it be "before"? Is 3000 miles too soon per verbal statements from GM? Is 4500 ok, per what you were told by your dealer? Is +/-1000 miles "not detrimental" as stated in the tech link article? How many would have said +/-500 is the limit?
You beat me to it. I read my owner’s manual right after I picked up my 2021 and it very clearly states the 7500 mile requirement filter change in a box marked “CAUTION.” I had my free filter change around 6000 miles and paid for it at 7100 miles.
I just looked at my 2022 Owner’s Manual and no where in the Service and Maintenance section does it have that boxed Caution note. It only has the maintenance table and footnote #5 stating to change the DCT filter at 7500 miles, with no + or - 500 mile leeway. As RKCRLR has stated, that boxed Caution note would have been very beneficial in emphasizing the importance of that first DCT filter change, if it had been in the earlier OMs.
I was referring to the caution note that isn't in the 2020 manual. Yes, there has always been a requirement to change the DCT filter at 7,500 miles, I'm not disputing that. What I'm disputing is that it is "clear" that that statement should have been interpreted if you change it earlier than those intervals that you need to change it again on those intervals.
Here is the note from page 292:
"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."
Notice that there is no reference to the 15K mile interval after the first filter change, but that is a different matter. So if that statement is supposed to mean you can't change it earlier than 7,500 miles without changing it again at 7,500 miles then what about the subsequent intervals? If you change your DCT filter at 21,000 miles do you need to change it again at 22,500 miles? Or if you change it at 43,000 miles do you need to change it again at 45,000 miles?
I just looked at my 2022 Owner’s Manual and no where in the Service and Maintenance section does it have that boxed Caution note. It only has the maintenance table and footnote #5 stating to change the DCT filter at 7500 miles, with no + or - 500 mile leeway. As RKCRLR has stated, that boxed Caution note would have been very beneficial in emphasizing the importance of that first DCT filter change, if it had been in the earlier OMs.
I have a 2022 Z51 HTC and for maintenance saw that the DCT filter was to be replaced at 7,500 miles. Having owned cars for about 50 years I interpreted the 7,500 mile recommendation to include a modest "plus or minus." I had the filter changed at 7,843 miles and again at 22,625. I did not find the maintenance schedule confusing or hard to understand and have been enjoying the car which is approaching 42,000 miles on the odometer. I also understood that the DCT fluid was recommended to be replaced at 45,000 miles or 3 years, whichever comes first, and had this service done at 33,167 miles when the car was 35-1/2 months old. I do not waste resources and money by doing more maintenance than called for and try not to overthink stuff. Just follow the simple directions and be reasonable. Such a mindset applies to most things in a successful life.
Last edited by Bob Paris; Jun 29, 2025 at 05:44 PM.
Unfortunately, there are other instances where it says "must be changed at...." where so called common sense says it really mean "must be changed at or before .....".
Here are two examples:
"If the system is ever reset accidentally, the oil must be changed at 5 000 km (3,000 mi) since the last oil change." So, does this mean if accidentally reset you are only allowed to change the oil at 3000 miles then? Or can it be anything less than 3000miles. Experience tell us that it really means at or before.
"If the system is ever reset accidentally, the fluid must be changed at 72 000 km (45,000 mi) since the last fluid change." Experience tells us it means at or before.
How does a non-forum member know that when it is about the filter "the filter must be changed at 7500", it does not mean "at or before", it means (as it turns out) 7,500 +/-500 miles even if changed before.
^^^ SIDEBAR (but relevant)
Been a Member of our Tech Societies "Technical Activates Committee" for many years (still am.) Some ~40 volunteers are members by virtue of being Chair of a Main Standards Committee. We are required to review and approve over a hundred Standards revised and reissued each year.
In the few meetings held each year, we will periodically review where "Should, "Shall," "Must," "Required" are used. We're not consistent in our several hundred welding standards documents, like the several hundred page Bridge Code, or for Buildings, Aircraft, Earth Moving Equipment etc. The Doc's are used World Wide which make it even tougher.
Recall when we asked our Society attorney (The Law Firm specializes in Tech Societies) to comment when we were rewriting our rules. And like typical attorneys, fact is no matter what "word" is used, in Court it can be interpreted differently especially when used differently in the same or other similar documents. He suggested the best thing we could do (and are trying) is be consistent!
