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  • Burnt clutches
  • Erratic line pressure
  • Low converter & lube flow
  • Overheating
  • Poor shift quality
  • TCC apply & release concerns


Continuous oscillation of pressure regulator valve results in excess bore wear, allowing line pressure to exhaust and/or blocking converter feed oil.


Restore line pressure performance and renew converter feed by reconditioning the bore and installing Sonnax oversized pressure regulator valve kit.

6T30, 6T40 (Gen. 2), 6T45 (Gen. 2), 6T50 (Gen. 2)

Oversized Pressure Regulator Valve Kit
Part No. 144510-12K

You need this if... View Instructions

Listed second generation transmissions may exhibit multiple line pressure and converter-related problems due to wear of the main pressure regulator bore. Wear at the balance spool end allows critical fluid loss, resulting in excess line pressure, harsh shifts, and reduced cooler/converter flow. Wear at the outboard spool robs converter feed pressure and lowers line pressure, resulting in soft shifts and burnt clutches.

Reconditioning the bore and installing Sonnax oversized pressure regulator valve kit 144510-12K restores hydraulic integrity for proper line pressure control in all ranges.

  • Oversized pressure regulator valve and matched spring restore OE function
  • Hardcoat anodized aluminum valve combats premature wear
  • Valve
  • Sleeve
  • End Plug
  • 144510 12k combo
  • 144510 12k

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

  • 144510 12k in test