FNR5 Transmission Valve Body with Solenoids Mazda 3

This is the complete FNR5 valve body, assembled with its solenoids and separator plate, for the Mazda FN4A-EL / FS5A-EL five-speed automatic that Ford also badged as the FNR5. It is the transaxle used in the Mazda 3 2.3L, Mazda 5, Mazda 6 2.3L and 3.0L, Mazda 8, and in the 2006-2009 Ford Fusion and Mercury Milan with the 2.3L and 3.0L V6. If your case tag reads FNR5, FN4A-EL or FS5A-EL, this is the hydraulic body that bolts to it.

The FNR5 fails in a pattern most shops recognize before the car is off the lift: a delayed or flaring 2-3 shift, a hard 1-2 bang once the fluid is warm, slipping in 4th, no upshift past 3rd, or the transmission dropping into limp with shift solenoid and pressure control codes stored (P0751, P0756, P0761, P0766, P0745). The root cause is nearly always the valve body: the aluminum bores wear oval around the pressure regulator and shift valves, and the pulse-width solenoids on the body lose their ability to hold a commanded pressure. Once the bores are worn there is no fluid service, filter or flush that brings the shift quality back - the body comes off. Replacing the assembled unit changes the whole hydraulic circuit and the solenoids together instead of chasing one valve, which is why it is the repair that actually sticks.

Bench and in-car procedure: drain the transaxle, drop the pan, unplug the internal harness connector at the case pass-through, and pull the filter. Back the valve body bolts out from the outside in so the casting comes down flat and the check balls and the two accumulator springs stay seated - lay them out in the order they come off, the FNR5 bolts are not all the same length. Set the replacement body on the case dowels, start every bolt by hand before torquing, and pull them down in a cross pattern so the separator plate seats evenly. Reconnect the harness, fit a new filter and pan gasket, then fill with Mazda ATF M-V (Ford Mercon LV on the Fusion and Milan) and set the level at the specified fluid temperature at the check plug, not by guess. Clear the codes and relearn the adaptives on a road cycle before you judge the shift quality - the first few miles will shift firm while the TCM re-adapts.

Ships new and fully assembled with the solenoids installed. The pan gasket and filter are not included - order those with the job, because neither should be reused on a valve body replacement.