FNR5 FN4A-EL Transmission Filter & Pan Gasket Kit, Mazda 3/5/6

This is the internal filter and pan gasket for the FN4A-EL / FNR5 five-speed automatic, the Aisin-built transaxle Ford and Mazda co-developed and ran under a lot of common cars. It also carries the FS5A-EL, 5F27E, 4F27E and J39A designations, and it replaces ATP 044-0393 and Ford/Mazda 6E5Z-7B155-A (FNC1-21-500). You will find this unit in 2006-2013 Mazda 3, 2008-2014 Mazda 5, 2006-2013 Mazda 6, 2011-2014 Mazda 2 and 2010-2012 CX-7, plus the 2006-2009 Ford Fusion, Mercury Milan, and Lincoln MKZ and Zephyr four-cylinder cars.

On the bench the job is straightforward: drop the pan, pull the old screen-and-gasket filter off the valve body, and set the new one in before you reseal the deep pan. The pan gasket comes in the kit, so the pan lands on a fresh seal instead of old RTV. Torque the pan bolts evenly and refill with the correct Mazda/Ford five-speed ATF to level. This is the filter and gasket you install during a fluid service or any time the pan is off for a valve body or solenoid job.

A clogged FN4A-EL filter starves the pump and shows up as a slip or flare on the 1-2 and 2-3, a delayed or harsh engagement when cold, or a whine as the pump pulls against a restriction. These filters load up with clutch material as the miles climb, so on a high-mileage 3, 5 or 6 the filter goes back in new with every fluid change rather than getting reused.