Change Fluid???
If your tranny uses non-synthetic Mercon, the lubricating properties in the fluid start breaking down after about 30K, that's normally when you would change it. If you have the synthetic Mercon V fluid, the lubricating properties never break down, but the fluid still gets dirty, so it won't hurt to change it at 30K either.
I would change it every 30,000 for peace of mind if you have the money...
This was my transmission filter at 39,000 miles...

And the pan magnet...
The pan magnet comes off and all those metal particles can be wiped off...
This was my transmission filter at 39,000 miles...

And the pan magnet...
The pan magnet comes off and all those metal particles can be wiped off...
That's how mine looked at 42,000. I drained both the torque converter and pan, replaced the filter, and added 15.5 qts of Mobil 1 ATF. Nice and clean again and the common Ford transmission shudder was gone.


