I drained the oil from my th400 transmission and it has some silver and red color like material in the bottom of the Black Plastic drain pan when emptied, held vertical and light shining on the pan. This looks very-very fine and does not show up when strained through a paint filter.

Is this a problem and why?

Just my opinion, but if it doesn't even show on a paint filter, it is not an issue. Take care. Tom Worthington

rub a magnet around in it and see if it's steel.

If this is first time you have changed the fluid in this transmission then I would say that is normal.
If you have changed the fluid before and it never showed this sign before then you may have a issue. If the trans is working properly then you likely do not have a issue.

Good idea to talk with your transmission builder so atleast they know.

Jerry

quote:

rub a magnet around in it and see if it's steel

It does not attach to a magnet, but when you look at it running down the back of a black pan held vertical, I wonder exactly what this is.

Today I placed a cone type coffee filter in a funnel and filled it to the rim with this fluid in the pan. It took almost an hour to filter through. And when I tore the filter to spread it out there was nothing there that resembled what was in the pan bottom…. it was clean.

I’ve seen this before in my trans fluid changes but still wonder what I’m seeing.

It likely Friction material which are sometime red. Or if you run red trans fluid it could be it getting broke down.

You can send a sample to a lab and they might be able to tell you.

Also material from the steels, where the band contacts the drum, and other bushing wear.

You can't have clutches and bands grabbing steel parts at high rpm, and expect to never get anything in the pan. My glide pan always has that fine stuff in it.

quote:

...when you look at it running down the back of a black pan held vertical...

If you want it to really show up shine a flashlight beam on it.

quote:

If you want it to really show up shine a flashlight beam on it.

That’s Exactly what I did and required for full effect!

and dont forget, converters are always making a little "dust" as well. ALso, if a builder used the newer carbon clutches in your trans, then you will see a black dust everywhere. Drain and refill, it will be fine.