When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The 2023 and newer C8s have a DCT filter life monitor (not to be confused with the DCT fluid life monitor which all C8s have). The DCT filter life monitor percentage should count down to 0% around 7500 miles. However there is some confusion on whether the second DCT filter change should take place at 15,000 miles after the first DCT filter change (22,500 miles on the odometer) or at 22,500 miles after the first DCT filter change (30,000 miles on the odometer). The answers to the following questions should help resolve this (assuming the DCT filter life monitor was reset when the DCT filter was changed):
1) How many miles since your last DCT filter change?
2) What percentage is showing for the remaining life of the DCT filter?
2023 with 21500 miles and car is in service for 2nd transmission filter replacement. Transmission fluid life at 52%.
transmission filter life was at 4% and oil was at 3%.
Will pick up car today then can post actual milage of last filter change. I believe it was 7100, a little early but wanted both oil and transmission service done on my free service.
Milage when filter says it’s time to change can vary depending on how it was driven.
2023 with 21500 miles and car is in service for 2nd transmission filter replacement. Transmission fluid life at 52%.
transmission filter life was at 4% and oil was at 3%.
Will pick up car today then can post actual mileage of last filter change. I believe it was 7100, a little early but wanted both oil and transmission service done on my free service.
Milage when filter says it’s time to change can vary depending on how it was driven.
Unlike the other monitors, where the manual says they account for multiple factors, the manual seems to says the filter life monitor goes exactly in accordance with the number of miles driven as outlined in the Service and Maintenance section. So, I believe it is based on miles and not how it is driven. But, that is something we could confirm with forum reports. But we need the miles at each reset.
From the Manual:
"This vehicle has a computer that indicates when to change the transmission external canister fluid filter. This is based on the number of miles driven as outlined in the Service and Maintenance section."
Just checked. '23, 4982 miles. Changed fluid and filter at 2450. Fluid life at 94%. Filter life at 89%. Based on these numbers, the change intervals are close to the OM. Will be tracking the car starting next week and will see if the "linearity" changes.
2024, ~2350 miles... the oil life (68%) and DCT filter life (69%) are tracking very close to each other. Looks like I'll have no issues with getting the oil and DCT service done during the same visit, probably in 3-4 months.
2023 with 21500 miles and car is in service for 2nd transmission filter replacement. Transmission fluid life at 52%.
transmission filter life was at 4% and oil was at 3%.
Will pick up car today then can post actual milage of last filter change. I believe it was 7100, a little early but wanted both oil and transmission service done on my free service.
Milage when filter says it’s time to change can vary depending on how it was driven.
(21500-7100)/(1-0.04)=15,000. This supports that the second filter change is at 22,500 miles on the odometer. It also supports that GM believes that the DCT isn't fully broken (with regards to excess contamination generation) in until it has 22,500 miles on it. It looks like they made the first interval at 1/3 of the final change interval, the second interval is 2/3 of the final interval (double the first interval), and the third interval and beyond is the final interval of 22,500 miles. It will be interesting to see if the data continues to support this.
I forgot to mention it is also important to state whether this is your first, second, or third, etc. DCT filter change.
As @Andybump mentioned the owners manual states that the DCT filter life monitor is based strictly on mileage.
Just checked. '23, 4982 miles. Changed fluid and filter at 2450. Fluid life at 94%. Filter life at 89%. Based on these numbers, the change intervals are close to the OM. Will be tracking the car starting next week and will see if the "linearity" changes.
This is interesting. (4982-2450)/(1-0.89)=23,018 which suggests your interval is 22,500. Did you perhaps reset your filter monitor twice already?
This is interesting. (4982-2450)/(1-0.89)=23,018 which suggests your interval is 22,500. Did you perhaps reset your filter monitor twice already?
No, just reset at the 2450 mile replacement. I suspect based on my data that the car just clocks down on 22.5K increments. Up to us to change at 7500. From what I recall, the life monitor at 2450 miles was not at 67% but in the high 80's or low 90's percentage wise.
No, just reset at the 2450 mile replacement. I suspect based on my data that the car just clocks down on 22.5K increments. Up to us to change at 7500. From what I recall, the life monitor at 2450 miles was not at 67% but in the high 80's or low 90's percentage wise.
Your data implies 22.5K increments but see post #7. @wayback 's data implies that the second increment is 15K miles. At this point I'd trust his data more since he was close to 0% life left.
@Dan Hintz 's data supports that the computer knows that the first change interval is at 7500 miles. 2350/(1-0.69)=7581.
It will be interesting to see what your data does in the future.
One thing I wonder about is what dealers do to the maintenance life monitors before they deliver a vehicle to their customers. If a car has sat on the lot for awhile (or took a long time in transit) they don't want the customer complaining about having to bring the car back in 6 months for an oil change. So some may be in the habit of resetting the monitors prior to delivery. This will work for most monitors but wouldn't work for the DCT filter life monitor if it reflects different increments for the first and subsequent changes.
We will see. Perhaps the life monitor isn’t linear. It’s not a matter of trust per se as my car’s data/info is what it is. Filter changes at 2450 and monitor life reset for both the fluid and filter. Will be interesting to see if the life decrement changes not in proportion to the miles after the next two weeks of track time. Weather permitting it’ll be between 3 and 4 hours on the track.
Based on the above post it would perhaps mean that if you reset the filter life prior to 7500 miles it will clock to 22.5K miles. His mileage and life clock down to 7500ish which makes sense based on the 7500 first change requirement. BTW, Tadda’s car and mine were built on the same day. Not that it matters in this discussion but cool nonetheless
Now lets have folks chime in that changed their filter prior to the 7500 mile mark and let us know what the filter life percentage is. I bet it'll clock to zero around 22.5K miles.
I was told by a friend, a certified C8 mechanic, you should always trust the maintenance monitor. It accounts for a number of factors, of which mileage and time are accounted for as well as many others. The monitors are based upon GM guidelines.
Now lets have folks chime in that changed their filter prior to the 7500 mile mark and let us know what the filter life percentage is. I bet it'll clock to zero around 22.5K miles.
Are you saying that if you reset the DCT filter life monitor for the first time prior to 7500 miles it will give you a different answer than if you reset it for the first time after 7500 miles? Or are you saying you think it will always clock down to a 22.5K mile interval after the first reset?
I was told by a friend, a certified C8 mechanic, you should always trust the maintenance monitor. It accounts for a number of factors, of which mileage and time are accounted for as well as many others. The monitors are based upon GM guidelines.
The question isn't about trusting the DCT filter life monitor so much as it is what will the mileage interval be after the first reset. 15K miles or 22.5K miles? So far we have one data point that suggests 15K miles and one data point that suggests 22.5K miles. We now have several data points that the monitor knows about the first 7500 mile DCT filter change.
The owner's manual only mentions that the DCT filter life monitor tracks mileage which implies that it doesn't track anything else. The manual specifically mentions that the engine oil life and DCT fluid life monitors monitor other things besides mileage. And we know for sure that you can't trust the DCT fluid life monitor to track the 3 year DCT fluid change requirement.
Are you saying that if you reset the DCT filter life monitor for the first time prior to 7500 miles it will give you a different answer than if you reset it for the first time after 7500 miles? Or are you saying you think it will always clock down to a 22.5K mile interval after the first reset?
I’m suggesting that the counter will count down to 22.5K after the first reset even if done prior to 7500. And suspect it will clock every 22.5K thereafter.
04-10-2024, 11:35 AM
What is your DCT Filter Life Percentage?
