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This thread is not a debate about whether to change the DCT filter before 7500 miles or 1 year. I have already decided that I (not the dealer) am going to change the DCT filter soon after the break-in period ends (currently at 300 miles). My question is how far outside of the break-in period should you change it? 500, 1000, 1500 miles? I work from home so I don't put a lot of miles on the car and I will change it out within a year at the latest regardless of the miles. If the DCT starts acting up, I'll change the DCT filter right away.
I appreciate any advice from those who changed out the DCT well ahead of the GM recommended service. Again, this isn't a debate about whether or not you should change it before the recommended service. I have already made that decision. Thanks!
....... I (not the dealer) am going to change the DCT filter soon after the break-in period ends (currently at 300 miles). My question is how far outside of the break-in period should you change it? .......
I changed mine at 1 year, and 2500 miles, using the free service. I plan to change it again at 7500 miles at my expense. Other forum members have quote verbal advice from a GM rep that the "break-in" contaminants will continue to accumulate until 7500 miles, making it important to change the filter then, even if you have changed it earlier.
As for "how far outside the break-in peridod" it depends on which break-in period you are thinking about. The break-in period sections starts with a statement that the period is 1500 miles (see clip). Then it breaks it into 200, 500, and 1500 mile periods (as most know). But it also seems to imply that 7500 miles is the break in period for the transmission, in the context of the filter change (see clip below from the 2023 manual that says that).
First, here is the mention of the 7500 mile period:
And, here is the first sentence in the section on break-in, that appears to say the period is 1500 miles.
Here are the 200 and 500 mile periods:
And, finally the 1500 mile period for "track events" and "similar activities":
This thread is not a debate about whether to change the DCT filter before 7500 miles or 1 year. I have already decided that I (not the dealer) am going to change the DCT filter soon after the break-in period ends (currently at 300 miles). My question is how far outside of the break-in period should you change it? 500, 1000, 1500 miles? I work from home so I don't put a lot of miles on the car and I will change it out within a year at the latest regardless of the miles. If the DCT starts acting up, I'll change the DCT filter right away.
I appreciate any advice from those who changed out the DCT well ahead of the GM recommended service. Again, this isn't a debate about whether or not you should change it before the recommended service. I have already made that decision. Thanks!
First the filter change requires a Flush prior per GM procedure. It's done by the GM Service Computer. Takes about 10 minutes all work done by the GM software. Tech and I watched with the engine running, his PC connected to GM Service Computer via WiFi and to my car via OBD. There are >14 valves that activate shift forks etc. Could hear "things happening!"
I had mine done with the 1st oil change at ~12 months <4000 miles. My plan is to change it again year 3 when all 11 quarts of DCT fluid require changing (per note 4 in the Maintenace Table.) Will have about 7000 to 8000 miles on that new filter, ~11,000 to 12,000 miles on the C8. That will be on my dime!
It appears that everyone has a different story. My car is at 1 year old now and I personally did my engine oil change a few weeks ago. I am now just over 6,000 miles on the car and engine, however, I am only at 4,000 miles on the transmission. I am not sure how this will work out. My dealer-tech says that GM will require the transmission flush with each transmission filter required change. As yet, I am not buying the transmission flush at succeeding intervals. Confusing to say the least.
I...My dealer-tech says that GM will require the transmission flush with each transmission filter required change. As yet, I am not buying the transmission flush at succeeding intervals. Confusing to say the least.
Not confusing, your tech is right! My tech showed me the GM procedure on his PC when he changed my DCT Filter last August. It said before removing filter do a DCT flush. It will wash any debris (in the ~14 DCT valves etc) into the filter and filter housing before replacing the filter and removing fluid from the housing.
He connected to my C8 (with engine running) and the GM Service Computer with his PC via WiFi. Program did all the work. Heard "things" happening as we watched for ~10 minutes then screen said "Flush Completed."
So you'll have GM do if free year 2 THEN year 3, per the Owner's Manual you will have all 11 quarts of DCT fluid changed and leave in that dirty (to some degree) filter and ~8 oz of dirty fluid in the housing. OR change a 1 year old filter!
Better if you want to do your own oil change (prior to my C8 changed all my own engine oil and filter even in my two C7's as FREE was not worth the risk of some newbie tech at the dealer messing up my two dry sumps! In fact have done that with ever DD since my 1st car in 1959. ) Fortunately found a small dealership where only a very skilled Vette Tech does everything related to the C8. I could do my own oil change in August for year two BUT for the 3 year 11 quart replacement I'll have him do that and change my then 2 year old DCT filter with ~7000 miles.
PS: Just a note, I often don't post for the Vocal Minority posters like myself as they have their mind made up! BUT there are many more Silent Majority member's who only view threads, some won't post! They are viewing because they are interested in the subject. I'm providing an alternate suggestion! This post is typical of the ratio; ~4 Vocal Minority Posters and already ~300 who viewed!
Not confusing, your tech is right! My tech showed me the GM procedure on his PC when he changed my DCT Filter last August. It said before removing filter do a DCT flush. It will wash any debris (in the ~14 DCT valves etc) into the filter and filter housing before replacing the filter and removing fluid from the housing.
My point was, is it required to have the dealer do a flush before each filter change?
Not confusing, your tech is right! My tech showed me the GM procedure on his PC when he changed my DCT Filter last August. It said before removing filter do a DCT flush. It will wash any debris (in the ~14 DCT valves etc) into the filter and filter housing before replacing the filter and removing fluid from the housing.
He connected to my C8 (with engine running) and the GM Service Computer with his PC via WiFi. Program did all the work. Heard "things" happening as we watched for ~10 minutes then screen said "Flush Completed."
So you'll have GM do if free year 2 THEN year 3, per the Owner's Manual you will have all 11 quarts of DCT fluid changed and leave in that dirty (to some degree) filter and ~8 oz of dirty fluid in the housing. OR change a 1 year old filter!
Better if you want to do your own oil change (prior to my C8 changed all my own engine oil and filter even in my two C7's as FREE was not worth the risk of some newbie tech at the dealer messing up my two dry sumps! In fact have done that with ever DD since my 1st car in 1959. ) Fortunately found a small dealership where only a very skilled Vette Tech does everything related to the C8. I could do my own oil change in August for year two BUT for the 3 year 11 quart replacement I'll have him do that and change my then 2 year old DCT filter with ~7000 miles.
PS: Just a note, I often don't post for the Vocal Minority posters like myself as they have their mind made up! BUT there are many more Silent Majority member's who only view threads, some won't post! They are viewing because they are interested in the subject. I'm providing an alternate suggestion! This post is typical of the ratio; ~4 Vocal Minority Posters and already ~300 who viewed!
So are you saying I am wasting my time and money if I don't do the flush but change the DCT filter on my own prior to the scheduled GM maintenance at dealership? (I assume there are particles trapped in the filter as that's what filters do.) I was planning to add the additional 2 quarts of transmission fluid as I know a little bit of fluid is lost with the DCT filter change.
^^^
Yep. Your car BUT I would have the dealer change the DCT filter and perform a DCT flush. It's on GM's dime as is one engine oil replacement up to year 2.
As far as how many miles, you're determined to do it early, your choice. The C8 is my first DD since my 1st car in 1959 that was not a standard shift! (BTW changed all my own oil in all DDs including my 6 Vettes and even two C7s as the risks with a dealer tech screwing up my C7 drive sumps not worth the risk. Lucky have found a great Corvette tech for my C8 at the small Chevy dealer who did my Courtesy Delivery!)
Expected some issues and found as I crawled into my garage, as I did with my prior 2017 Grand Sport to keep the drivers' side mirror tip within 1 to 2 inches from the garage door wood molding (leaving plenty of room to the passenger mirror that is harder to judge) the car felt a bit jerky. With the Grand Sport would have been disengaging the clutch at that 3 to 4 mph and occasionally stopping as I have to make a 90 degree "K" turn to enter the garage and am not perfectly straight. That lasted ~800 miles then was perfectly smooth. Thought that was probably the 1st gear clutch disks wearing in. After that and now it's perfectly smooth. Keep in mind those multi-clutch disks are also slipping when stopped for a red light, etc.
In addition each of the 8 gears as synchros. Some, if not all, triple cones like most in my C7 M7s, some carbon faced. They take time to wear in. More of a wear issue than gears IMO. So I would wait min 1500 miles BUT THAT IS ME!
PS: If you decide to do a DCT filter change be careful, we had a poster shear the screws! It says 53 inch -bs BUT you first must chase the threads to remove the GM thread seal. The 4 new bolts that come with the filter kit are precoated. An "O" ring is doing the sealing so making the bolts snug is all that is needed.
Each of the 8 gears has syncros. Some if not all triple cone. Take some time to wear in.
^^^
Yep. Your car BUT I would have the dealer change the DCT filter and perform a DCT flush. It's on GM's dime as is one engine oil replacement up to year 2.
As far as how many miles, you're determined to do it early, your choice. The C8 is my first DD since my 1st car in 1959 that was not a standard shift! (BTW changed all my own oil in all DDs including my 6 Vettes and even two C7s as the risks with a dealer tech screwing up my C7 drive sumps not worth the risk. Lucky have found a great Corvette tech for my C8 at the small Chevy dealer who did my Courtesy Delivery!)
Expected some issues and found as I crawled into my garage, as I did with my prior 2017 Grand Sport to keep the drivers' side mirror tip within 1 to 2 inches from the garage door wood molding (leaving plenty of room to the passenger mirror that is harder to judge) the car felt a bit jerky. With the Grand Sport would have been disengaging the clutch at that 3 to 4 mph and occasionally stopping as I have to make a 90 degree "K" turn to enter the garage and am not perfectly straight. That lasted ~800 miles then was perfectly smooth. Thought that was probably the 1st gear clutch disks wearing in. After that and now it's perfectly smooth. Keep in mind those multi-clutch disks are also slipping when stopped for a red light, etc.
In addition each of the 8 gears as synchros. Some, if not all, triple cones like most in my C7 M7s, some carbon faced. They take time to wear in. More of a wear issue than gears IMO. So I would wait min 1500 miles BUT THAT IS ME!
PS: If you decide to do a DCT filter change be careful, we had a poster shear the screws! It says 53 inch -bs BUT you first must chase the threads to remove the GM thread seal. The 4 new bolts that come with the filter kit are precoated. An "O" ring is doing the sealing so making the bolts snug is all that is needed.
Each of the 8 gears has syncros. Some if not all triple cone. Take some time to wear in.
I think you talked me out of doing this myself. Not worth the savings to me for the time, effort, and risk. I'm big on doing things the right way and it appears I don't have the tools and technology to do that. Thanks for providing the insight.
It is puzzling for GM not to recognize the need for a DCT filter and/or oil change for the new c8. My BMW m4 with a similar 8-speed DCT required a fluid and filter change at 1200mi. With all-new engines and transmissions, it is advisable to replace fluids after the initial break-in to remove metal shavings and engine debris after the initial break-in. Longer engine life.
^^^
As I posted, at the most recent Bash in a seminar on C8 maintenance the GM rep said to have the DCT filter changed (which by GM specs required a flush first) at the first engine oil required change. With GM they will not go back and say they were wrong but with the DCT experience of a number of folks with little use getting CELs requiring a flush, they are getting smarter.
They had also said need to change DCT filter at 7500 miles as DCT continues to get initial wear. So my thought in August 2021 when I had about 3500 miles was to have the DCT filter changed with flush all on GM's dime. Then this August with ~7000 miles I'll just change the engine oil/filter. Year 3 will have the REQUIRED all 11 quarts of DCT fluid changed and the DCT filter with a flush. I'll have about 11,000 miles on the car and ~7000 on the filter replaced last year.
IMO smarter that paying a dealer for an oil change year one. If you want to pay a dealer (or change your own) do that year 2 and do what I'm doing year 3 when it's REQUIRED to have the 11 quarts of DCT fluid replaced!
Recently moved from FL and went to a local Chevy dealer and inquired about first oil change and transmission flush and filter and the tech recommended pay for the first oil change and get second oil change and transmission flush and filter closer to 7,500 miles or within two years that GM will cover. Car has 3,000 miles, 11 months and 18% remaining on oil life. Going to get a second opinion at another dealer that I am familiar with.
Any thoughts.
.... Going to get a second opinion at another dealer that I am familiar with.
Any thoughts.
That was what some forum members said BEFORE a recent member posted he was told at a recent GM Bash in a C8 Maintenance seminar to have both done on GM's dime when your 1st engine oil change is required.
That is the decision I made on my own last August for several reason with ~3500 miles on my 1-year-old C8. About where you will be:
I realized that year 3 you MUST, per the Owner's Manual, have all 11 quarts of DCT fluid changed.
I also was concerned about a number of forum reports of DCT CEL's, folks had that required a flush.
I had observed a slight jerkiness when crawling into my garage for about 800 miles- after, as now, it's perfectly smooth (see Sidebar)
So suggest doing what I did and am doing.
Year 1 have both engine oil and DCT filter changed (with GM required flush) on GM's Dime.
Year 2 pay the dealer to just change engine oil
Year 3 have the engine oil AND DCT filter changed again when in my case will have ~7000 miles on my 1st year new filter. Think it's better (although not essential) to change the filter and ~8 oz of dirty fluid in the filter housing and have a flush when all DCT fluid is replaced.
SIDEBAR
The 1st gear clutch (larger external shown below, also the clutch for 3rd, 5th, and 7th) slips when going less than 4 mph. Has to or the engine would stall! It also slips when stopped for a Red light etc. It does NOT disengage.
I crawl into my garage (as I did with my 2 prior C7 Vettes that were standard shift) to keep my driver's side mirror tip within 1 to 2 inches of the wood door molding. It's easy to judge and know if less than 3 inches have plenty of room on the right passenger door mirror that is harder to judge. Occasionally have to stop and creep forward. For the first ~800 miles felt a bit jerky. No doubt those 1st gear multiplate clutch disks we are wearing in. Wanted to get rid of what may have accumulated. Also, most gears have triple cone synchro's that will have higher initial wear. Perhaps why GM is now suggesting change the filter and have a flush together at the 1st oil change!
DCT is really two 4 speed standard transmission with shift folks and 8 sets of synchro cones. Most, if not all, are triple cones, one carbon faced as were those on my C7s. Initial wear on those, shift forks and gears usually is higher in that 1st 500 to 1500 miles. GM says change the filter at 7500 miles so do that year 3!
Recently moved from FL and went to a local Chevy dealer and inquired about first oil change and transmission flush and filter and the tech recommended pay for the first oil change and get second oil change and transmission flush and filter closer to 7,500 miles or within two years that GM will cover. Car has 3,000 miles, 11 months and 18% remaining on oil life. Going to get a second opinion at another dealer that I am familiar with.
Any thoughts.
That is also what my service writer recommended when I took mine in, in June 2022, at 2500 miles, but she was happy to whatever I wanted. I had the filter changed anyway, using the included "free service". As noted by others, because it has been stated by GM engineers that wear debris continues to accumulate up to 7500 miles, I will have my filter changed again then, if I reach 7500 miles before the three year fluid change is required. If three years comes first, I will likely have both the filter and the fluid changed. In my case, I am likely to get to 7500 miles right around the three year mark. As for whether it was necessary to change it at 7500 miles or not, I have nothing to offer, other than its what I chose to do. So far, I have had no issues with the car other than the water on the passenger floor issue, which I fixed myself.
I'm still confused. Brought the car in for my first oil change because the change oil light was on. The car was 13 months old with about 1700 miles. Service writer said GM will not pay for the flush and fluid change before 7500 miles. Is he right? If not and I'm within the 2 year deadline can I still have the flush and fluid changed on GM's dime?
I'm still confused. Brought the car in for my first oil change because the change oil light was on. The car was 13 months old with about 1700 miles. Service writer said GM will not pay for the flush and fluid change before 7500 miles. Is he right? If not and I'm within the 2 year deadline can I still have the flush and fluid changed on GM's dime?
1) No that's not right. They can do the change earlier, which I did at 2500 miles and 1 year and they will be reimbursed by GM for that. 2) Yes, you can have that service any time in the first two years. My service writer did advise me to wait, but I chose not to. I will have it changed again at 7500 miles or when I get to the 3 year mark, whichever is first (likely to be the same for me) when I have the fluid change. She did remind me that when I have it done the next time, it will be expensive. I knew that. As for rationale for early changes, others have covered that. To keep the warranty in effect it is only necessary to follow the required service as stated in the Owner's Manual.
I'm still confused. Brought the car in for my first oil change because the change oil light was on. The car was 13 months old with about 1700 miles. Service writer said GM will not pay for the flush and fluid change before 7500 miles. Is he right? If not and I'm within the 2 year deadline can I still have the flush and fluid changed on GM's dime?
She is wrong!
A person posted that at the recent GM Bash they attended a seminar on C8 Maintenace and e were told by GM Rep to have both the engine oil changed when the OLM stays (which is a max 12 months AND the DCT filter change with the required by GM flush.
You can have that done up to 2 years. May not get to 7500 miles in two years BUT if you want GM to pay it must be before 24 months. After that your dealer cannot apply for a warranty reimbursement.
Mine cost be zero at year one for both engine oil and DCT filter with flush.
I I siad in prior posts have doth done now on GM' dime. Year two pay for an oil change (or do yourself or have anyone doit, just keep receipts.
Then year 3 when the Owner's Manual says change all 11 quarts of DCT fluid can have the filter changed again (as I will) or NOT.
I'm still confused. Brought the car in for my first oil change because the change oil light was on. The car was 13 months old with about 1700 miles. Service writer said GM will not pay for the flush and fluid change before 7500 miles. Is he right? If not and I'm within the 2 year deadline can I still have the flush and fluid changed on GM's dime?
She is incorrect. However, if you chose to have GM pay for the first engine oil change then you can't go back and get the DCT filter changed for free.
DCT Filter Change
) Fortunately found a small dealership where only a very skilled Vette Tech does everything related to the C8. I could do my own oil change in August for year two BUT for the 3 year 11 quart replacement I'll have him do that and change my then 2 year old DCT filter with ~7000 miles.
