Not magnetic: What's the deposit in my ATF

[ordinarybloke]

Recently did a flush of my Volvo V70 using 3309 ATF. Known for issues, I put a 3/8" Magnefine filter in and after doing it saw lots of brown sludge in the old used ATF. Put a magnet over it, and it failed to be attracted.
It was even fien enough not to be filtered by the magnefine.

Now I'm used to seeing engine oil blackened, fair enough...
But in an Autobox? er, what am i looking at?

 

[exranger06]

Probably friction material from the clutches.

 

[Jim Allen]

Originally Posted By: exranger06
Probably friction material from the clutches.


I agree. Or oxidative residue from high heat. Or both.

 

[Donald]

Or aluminum from the TC. A UOA would tell for sure.

My Camry had somewhat high aluminum and the Magnefine did not catch it.

 

[ordinarybloke]

Thanks for the answers.
I was surprised the Magnefine did not catch it, it's a Aisin Warner box. Which I think is linked in with Toyota somehow, so the same box as your Camry... ish.

 

[demarpaint]

As mentioned non ferrous friction materials, and aluminum from the torque converter.

 

[Whitewolf]

I agree that it is probably friction material.

 

[RF Overlord]

He said it was brown sludge...that doesn't sound like aluminium to me. I'm siding with Jim Allen.

 

[MolaKule]

Quote:
..what am i looking at?


You didn't say how many miles of usage were on the fluid.

I think what you saw (from most to least) was a combination of very fine clutch material suspended in the fluid, oxidized fluid, and fine aluminum particles suspended in the fluid.