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Manufacturer Part Number: K74878

Other Part Number: S38507PK

Brand: Sonnax

F4A-EL, GF4A-EL

Pump Rebuild Kit
Part No. K74878

Includes Discharge Valve & Compression Spring

In the F4A-EL & GF4A-EL transmissions, when pump volume is too low, it causes low line pressure, which results in a 2-3 shift flare. Frequently these problems can be traced back to the pump's inability to flow oil to the pressure regulator. All pump volume flows through the spool valve to the regulator in the valve body. This spool valve position determines pump volume by overcoming the spring and exhausting output to suction. Sonnax has developed a pump rebuild kit K74878 for the F4A-EL & GF4A-EL pumps.

  • Kit includes a replacement spool valve with a specially designed inside diameter that reduces any restrictions.
  • Kit also includes a specially designed spring that will eliminate bore hang-up problems.
  • Spring is stiffer than the original version to better position the spool valve for improved pump volume.

Fits 1-pan style unit and 2-pan, 7-solenoid style units with gear pumps.

  • Spool Valve
  • Compression Spring

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