The internal trans filter on my Chevrolet El Camino is just a screen, and I think it has a 100 micon rating. The internal trans filter on my Mercury Marauder that I just changed has a felt type media. Does anyone know what the micron rating is for these felt type filters. My Marauder has a magnet inside the trans pan, and it did catch some stuff, I also have a Filtermag TM360 Trans Pan Magnet and this caught a little bit of debris. The problem with trans magnets is that they only catch metals that are magnetic, and aluminum is not one of them. I believe the Magnefine has a micron rating of 25 or 35, would this be a good idea or is this overkill. Has anyone put a Magnefine or an external transmission filter like the Permacool setup and noticed better shifting or cleaner trans fluid when they dropped the trans pan. Any thoughts would be appreciated.