September 30, 2005
Always measure the OE valve before reaming. The inboard smallest diameter must be .505" for this reamer & replacement valve!
Vehicles with a F4A-EL, FA4A-EL, F4EAT or F4E-III transmission often have low line pressure, high line pressure, harsh shifts, lack of cooler flow, and/or blued converters. Many times these problems can be caused by a worn valve body bore at the pressure regulator valve. If line balance or cutback feed pressure is allowed to leak, the valve can't regulate line pressure, so pressures remain high. TV balance pressure reduces line pressure in 2nd, 3rd and 4th gears, so leaks at these spool diameters can cause harsh shifts. If the bore is worn at the line pressure passage, valuable line pressure may exhaust to sump. Sonnax has developed an oversized pressure regulator valve 74846-06K for these applications. By reaming the valve body bore with Sonnax reamer kit 74846-TL6, this valve restores the hydraulic integrity of the circuits and prevents leakage.
It is highly recommended that the pressure modifier valve bore be checked for wear on the F4A-EL, FA4A-EL & F4E-III units as well. Wear at this bore can result in erratic shift quality and high/low line and EPC pressures. Sonnax offers an oversized pressure modifier valve, [74846-07K], which can be used to refurbish bore wear at this location. See instructions for appropriate part numbers and applications.