Ford FNR5

Transmission general data

The 5-speed automatic transmission FNR5 (FS5A-EL - Mazda, 5F27E - Ford) was designed in 2004 on the basis of the 4-speed automatic transmission 4F27E. This unit has several new elements, some upgrades in the valve body and settings of the control block for better acceleration characteristics, fuel saving and increase of smoothness in gear shifting. Since 2005, this transmission has been installed on FWD Mazda 6 (3-8) and Ford Fusion with the engine capacity from 2.0 up to 2.5 liters.

Technical issues and repair guidelines

A typical soft spot of this automatic transmission family lies in the combination Drum Reverse + Rear cover. Aggressive driving style leads to the Overdrive clutch burning. Another typical problem of the 4F27E transmission occurs in Mazda cars, namely, wear-out of the servo mechanism seat of the band Overdrive. This problem is caused by vibrations from operation of the worn-out drum brake band. This chain of malfunctions includes different minor problems like wearout of teflon rings located between this drum and the support of the cover, which are replaced during each overhaul even if these components have no indications of damage.

Valve bodies of this transmission for Mazda and Ford are different. The valve body for Mazda has two solenoids of the main pressure EPC (А and В). The most common problem of all present-day automatic transmissions is related to contaminated ATF clogging the valve body, that in chain order leads oil shortage in packages and burning of friction elements. Frictions in this transmission may serve quite reliably together with other spare parts and solenoids for 200 thousand kilometers and even more, under the condition of well-timed ATF change, filter replacement, and avoidance of frequent forced accelerations. The valve body requires standard cleaning and replacement of spare parts.

Traditionally, Mazda's torque converter quite early requires repair or replacement of worn-out friction lock -up simultaneously with cleaning of the valve body and replacement of the pressure solenoid. The lack of locking, unusually rapid contamination of ATF and leaks through the seal near the torque converter may be considered as the sign of repair necessity for the torque converter. Operation with the worn out torque converter leads to vibrations on the shaft of the oil pump and cranking of the pump bushing (at the first stage of wear). This problem also has a negative impact on the pump seal.