Ford/Mazda 4F27E, FN4A-EL, FNR5 and FS5A-EL units may exhibit multiple line pressure and converter-related problems due to excess wear in the pressure regulator bore. Wear at the balance spool end allows critical fluid loss, resulting in high line pressure, harsh shifts, and overheating due to reduced cooler/converter/lube flow. Wear at the outboard spool area robs converter feed pressure and lowers line pressure, causing soft shifts and burnt clutches and bands. Reconditioning the bore and installing Sonnax oversized pressure regulator valve kit 46892-01K restores hydraulic integrity for proper line pressure control in all ranges.
Contact a Sonnax Parts Distributor.
Vacuum test(s) at the port(s) indicated fail to hold the recommended minimum in-Hg.