This tool kit is no longer in production. Contact your distributor to see if they still have this product available.
When the balance spool bore in Mazda G4FA-EL units wears, the valve won't stroke to regulate EPC pressure. If the middle spool bore wears, line pressure will be allowed to exhaust. Sonnax oversized pressure modifier valve 74846-04 restores hydraulic integrity to the circuit by sealing these locations in the bore.
It is highly recommended that the pressure regulator bore also be checked for wear. A worn pressure regulator bore can result in low/high line pressure, harsh shifts, lack of cooler flow, and/or blued converters. Sonnax offers an oversized pressure regulator valve 74846-05 to restore the integrity of a worn pressure regulator bore.
To wet air test the bore for leakage, place a small amount of oil in the balance EPC circuit. While holding the valve in the unstroked position, follow with low air pressure (Figure 1). There should be minimal or no leakage through the neighboring line port. If excessive leakage occurs, the bore should be reamed and the OE valve replaced.