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I post this to request any of you who change your dct filter or have it changed can you post pictures of an autopsy of the filter here please?
Backstory
GM has shown concern regarding transmission debris in the fluid and has done studies on early dct filter collection to make sure they have the right intervals (my dealership was advised back in 2020 to collect all filters on all c8 Corvettes that came in the first year for any type of claim and to send the filter to GM.).
Current Data
We have very little.
Posters have autopsied their dct filters in the 2k mile and up range in mileage and they reported seeing dark fluid with transmission debris that looks a bit like jewelers rouge polishing compound bits.
Example from Warp Ten
My Story
I took delivery of the car with 2 miles on it. From the moment I drove it off the lot I put the transmission in TRACK mode purposefully during break in. I did this for two reasons:
1. Touring mode seeks out the highest gear for fuel economy meaning more gear changes and lugging the engine at 1200rpm. Bad for the engine.
2. Touring mode means smoother shifts and smoother shifts means more clutch slipping. Bad for transmission break-in.
Ive now driven the car 2912 miles with probably 20-50 quarter mile passes and launch controls. Being stuck in traffic on a road trip. Multiple high performance (150mph plus) datalogging sessions and below are the results of my dct filter change...
I found zero visible solid debris/ contaminants.
Yes we did the hydraulic system flush into the filter.
Summary
Maybe i got lucky or maybe my transmission break in procedure really worked. Who knows right now as we have such limited data....
...but if any of you read this and could collect your dct filter and open it up and show us what it looks like and list your
1. Mileage on filter
2. Mileage on car
3. Mileage on transmission fluid
4. Transmission Drive mode or modes used
5. Driving environment (performance, tracking, stop and go traffic, highway, city, short trips, road trips)
This can perhaps help us better understand why some transmissions look clean as a whistle and others are full of clutch debris.
If anyone reading this has yet to take delivery please consider driving with the transmission mode in track mode only until the first dct filter change and post your results.
Thanks for sharing. Interesting logic regarding your break in procedure thoughts. Proof is in the performance. I always cut and exam filters in my cars, will do with the C8 as well. Get a filter cutting tool, causes no debris from cutting and as easy as opening a can of beans!
Good points and I cant remember fully how I broke mine in but didn't want to baby it too much. For you suggesting track mode I would be more to advise Z mode. Track turns off some of the stability control etc and change in the steering. Maybe being new and if the rump down into it not fully familiar with the car be nice to have some of these controls in place. Also in Z you can change perimeters and have the trans adjusted to full but steering and if w/mag ride change that so its not riding rough the whole time like in track.
I am close to that 2k mark and do plan to change mine out and will analysis it.
Good points and I cant remember fully how I broke mine in but didn't want to baby it too much. For you suggesting track mode I would be more to advise Z mode. Track turns off some of the stability control etc and change in the steering. Maybe being new and if the rump down into it not fully familiar with the car be nice to have some of these controls in place. Also in Z you can change perimeters and have the trans adjusted to full but steering and if w/mag ride change that so its not riding rough the whole time like in track.
I am close to that 2k mark and do plan to change mine out and will analysis it.
Yes and sorry i didn't clarify better that its just putting the transmission into track mode.
You can do that by running the drive mode in track mode or you can just set the transmission to track mode in your z-mode settings and only drive in z-mode.
This is actually what i do as i like my steering light. Personal preference.
Going to disagree with bhvrdr. While you may have no large debris, the filter is clearly full of the small sintered-type materials that are showing on your white paper towel - that which you termed "debris that looks a bit like jewelers rouge polishing compound bits". If you let the element dry (or wash out the element) you'd be amazed at how much of that material there is. If I had pulled this filter at 2,900 miles I would be glad that I did before any further debris build up.
Here's mine from 2,500 miles. No transmission issues at this point. Followed the 1,500 mile break-in followed by increasingly spirited driving. Minimal city-type use.:
Exterior with cage removed ("Clean" side) Exterior of element ("clean" side) Inside of element ("Dirty" side)
A new transmission was installed at 3,500 miles (case porosity) and here is the filter from that at trans mileage 2,000; vehicle mileage 5,500. Followed the 1,500 mile break-in procedure. Minimal city-type use:
End caps. No reason to believe that the relief valve had ever opened but it was very firmly "stuck" in the closed position. Made a point of exercising the valve on the new filter prior to installation. Outside view ("Clean" side) Inside 1 ("Dirty" side) Inside 2 ("Dirty" side) Inside 3 ("Dirty" side) Example of how the fine debris looks after drying and how easy it becomes a fine powder that wipes away
What I personally observed on the second change was how easily the debris on the filter moved and that the way you handle the filter can impact what you "see" and the conclusions you draw. I included the three inside (dirty side) to try and show this. Each picture is of the same area but you can see that the debris in the filter pleats was displaced as I handled the filter and stretched it open. Much of it found its way into the container I was using and the paper towel is a wipe across that container.
My observations is primarily that the way you remove and handle the filter can significantly impact what you see.
When you remove the filter canister the DCT fluid draining from inside the filter can start to wash any debris towards the lower part of the filter.
When you remove the filter you need to keep it as upright as possible and place it in a clean, dedicated pan/container. If you lay it down or into an oil collection pan, there is a good chance that much of the debris will be carried out by the remaining, draining DCT fluid.
When you open up the filter, what you see may not be what you get! The powdery debris seems to flow with the DCT fluid as it drains from the pleats and the mere act of opening up the pleats seems to encourage the movement of the debris from the pleats. So you need to look not only at the debris you can see on the pleats but also the amount of debris that has moved into the container. And the latter can be significant!
Going to disagree with bhvrdr. While you may have no large debris, the filter is clearly full of the small sintered-type materials that are showing on your white paper towel - that which you termed "debris that looks a bit like jewelers rouge polishing compound bits". If you let the element dry (or wash out the element) you'd be amazed at how much of that material there is. If I had pulled this filter at 2,900 miles I would be glad that I did before any further debris build up.
Here's mine from 2,500 miles. No transmission issues at this point. Followed the 1,500 mile break-in followed by increasingly spirited driving. Minimal city-type use.:
Exterior with cage removed ("Clean" side) Exterior of element ("clean" side) Inside of element ("Dirty" side)
A new transmission was installed at 3,500 miles (case porosity) and here is the filter from that at trans mileage 2,000; vehicle mileage 5,500. Followed the 1,500 mile break-in procedure. Minimal city-type use:
End caps. No reason to believe that the relief valve had ever opened but it was very firmly "stuck" in the closed position. Made a point of exercising the valve on the new filter prior to installation. Outside view ("Clean" side) Inside 1 ("Dirty" side) Inside 2 ("Dirty" side) Inside 3 ("Dirty" side) Example of how the fine debris looks after drying and how easy it becomes a fine powder that wipes away
What I personally observed on the second change was how easily the debris on the filter moved and that the way you handle the filter can impact what you "see" and the conclusions you draw. I included the three inside (dirty side) to try and show this. Each picture is of the same area but you can see that the debris in the filter pleats was displaced as I handled the filter and stretched it open. Much of it found its way into the container I was using and the paper towel is a wipe across that container.
My observations is primarily that the way you remove and handle the filter can significantly impact what you see.
When you remove the filter canister the DCT fluid draining from inside the filter can start to wash any debris towards the lower part of the filter.
When you remove the filter you need to keep it as upright as possible and place it in a clean, dedicated pan/container. If you lay it down or into an oil collection pan, there is a good chance that much of the debris will be carried out by the remaining, draining DCT fluid.
When you open up the filter, what you see may not be what you get! The powdery debris seems to flow with the DCT fluid as it drains from the pleats and the mere act of opening up the pleats seems to encourage the movement of the debris from the pleats. So you need to look not only at the debris you can see on the pleats but also the amount of debris that has moved into the container. And the latter can be significant!
thank you so much for posting that!
For clarification
I removed the white plastic screen that covers the actual filter media. For your picture can you remove yours?
If i rub paper towel on the media that still has the plastic mesh on it i get no dark color at all.
I collected both the filter and the fluid dropped with it directly falling into a new clear bag. All fluid in the filter was retained in the bag
Someone posted an updated GM ID document # on the DCT filter service. That specified the flush procedure before filter change. Does anyone have the ID #? I had it book marked, but lost them all in a computer problem. Thanks.
Mike (OP): I just saw this thread after I had my 1700 mile DCT filter changed including the flush at the dealer. The filter looked the same as yours with no signs of metal. Marcus, the Corvette tech at Criswell Thurmont, showed me the filter and said it looked quite good as he has seen some with metal particles. I have only driven my 2021 C8 Z51 Mag Ride in Z mode (with + 2 quarts DCT fluid) and religiously up/down shifting many times to insure sufficient DCT break in. There have been no DCT issues as well as no problems with the car. Overall, I am extremely pleased with the car and when I have the need to manually row through the gears, I take out my C6 Z51.
Bill
Mike (OP): I just saw this thread after I had my 1700 mile DCT filter changed including the flush at the dealer. The filter looked the same as yours with no signs of metal. Marcus, the Corvette tech at Criswell Thurmont, showed me the filter and said it looked quite good as he has seen some with metal particles. I have only driven my 2021 C8 Z51 Mag Ride in Z mode (with + 2 quarts DCT fluid) and religiously up/down shifting many times to insure sufficient DCT break in. There have been no DCT issues as well as no problems with the car. Overall, I am extremely pleased with the car and when I have the need to manually row through the gears, I take out my C6 Z51.
Bill
Thank you very much for your feedback Bill!
May i ask what your z mode settings are for transmission shifting?
Mike - Other than Suspension and PTM, all Z modes are set to maximum values. The Suspension is set to the mid-point. As I previously mentioned, I enjoy doing a lot of shifting as it seems to make me feel more in control of the car but use the 'D' setting and not the 'M' setting. D setting may exercise the valve body more than the M setting?
DCT Filter Autopsy
