23 Turbo, transmission filter under scope

[ruthrj]

Hey all! Transmission pan drop with filter and fluid replacement went well this week. 30k miles on the car and transmission filter for reference. I cut some of the filter media out for grins and giggles to see what its catching. Nothing crazy in there. I dried it out by pinching the media in a shop towel, and it was cool how much forbidden glitter transferred to the shop towel. Filter is doing its job

The little bits of what look like sand in the filter are metal. Had lighting held at steep angle with respect to the media so the media is quite dark in that pic. I flipped the media over and took a picture of the backside with light straight down on it to show how its constructed. Did one more in front of a window to show the mesh structure better. The media has large crosshatch threads, and the super fine threads of the filter are held together by that larger crosshatched mesh. Last picture is a representative pic of what the media looks like under 4x objective on a microscope. Honestly not sure what magnification the scope's camera itself is, guessing 5 or 10x so that scope picture is likely 20-40x magnification.

Found some bits of metal here and there. There is MUCH more dark non-reflective material in the filter. I'm guessing this is friction material from the transmission? Looks like carbon. Dark somethings. The microscope picture is a little deceptive. The media is by no means clogged even though it looks like there's a ton of material present in that scope picture. Wish I could compare to a new filter.

The condition of the magnet in the pan at 30k on my '23 T looked just like the condition of my '13 2.0 NA's magnet at 100k miles. Fluffy donut. Felt good wiping that sludge off. Pan itself was clean on the bottom, no sludge there.

 

[Lazy2.5]

There is MUCH more dark non-reflective material in the filter. I'm guessing this is friction material from the transmission? Looks like carbon. Dark somethings.

Yes.

 

[Boland01]

Our 2023 CX5 Turbo is only at 17K miles. I was just going to do a drain and fill at 30K but may consider dropping the pan and changing the filter too. Thanks!

 

[ruthrj]

No problem!

I fell down a rabbit hole looking up wear and transmission contamination and stumbled on old papers from Eleftherakis and Khalil (90’s). Thanks BITOG! They found 75% of transmission contaminants originate during the first 5k miles of use and then the transmission enters a steady state and produces 25% more over the life of the transmission. It goes deeper than that defining Type I vs II contaminants but it was really cool learning how modern transmission designs were affected by that research. Modern manufacturing processes do a better job removing manufacturing debris prior to entering service.

It seems the magnet and filter in a transmission do a good job catching that debris and holding on to it for the life of the assembly, hence the “lifetime” fill per Mazda and other manufacturers. I’m guessing that’s why the magnet on my old ‘13 at 100k miles looked like the magnet on my ‘23 at 30k. I’d be surprised if there was that much material on the magnet if I were to drop the pan in another 30k miles on the ‘23 but I could be wrong.

I don’t think I’ll change the filter again for the life of the vehicle. Maybe I’ll feel more up to it in another 100k miles? I got that surge of break in material out by changing the filter and cleaning the magnet. I think 30k miles fluid change intervals (thanks for the suggestion @sinistriel@) should work just fine to keep the fluid fresh and remove some of the finer non-magnetic contaminants that the filter can’t catch.

Check @Digbicks1234 thread, removing and reinstalling the pan isn’t for the faint of heart. Their writeup is by far the most in-depth writeup for the procedure. This was the third time I’ve done this type of service and I’m comfortable doing it, but it’s a pain for a novice like myself keeping surfaces clean and hoping you don’t have a leak with the new RTV.