September 30, 2005
Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits
Gregg Nader
Symptoms:
- Loss of cooler flow
- High line pressure
- Low line pressure
- Harsh shifts
- Overheated converter
- Blued converter
- No cooler flow
Cause:
The constant oscillation of the pressure regulator valve results in bore wear, which allows valuable oil leakage and improper functioning of the valve.Correction:
Sonnax oversized pressure regulator valve eliminates oil leakage and restores proper function to the valve.Warning:
Always measure the OE valve before reaming. The inboard smallest diameter must be .505" for this reamer & replacement valve!
Required tool kit 74846-TL6 is no longer in production. Check with your distributor for availability.
F4A-EL, F4E-III, F4EAT, FA4A-EL
Oversized Pressure Regulator Valve
Part No. 74846-06K
-
Tooling:
- 74846-TL6
View Instructions Find a Distributor
Vehicles with Mazda F4A-EL, FA4A-EL, F4EAT or F4E-III transmissions 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 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.
- Spring seat on the valve has been modified to compensate for the oversized valve
- Valve provides higher line pressure at idle
- Salvages expensive, hard to find valve bodies
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.
