• Erratic line pressure
  • High governor pressure
  • 2nd Gear starts
  • Delayed engagement
  • Harsh Reverse
  • Pressure over 230
  • No TV control
  • Overheated converter
  • Blued converter


Bore wear at the pressure regulator valve on high-mileage vehicles allows orificed balance line pressure to leak to the sump and affects converter feed and line pressure control.


This replacement pressure regulator valve incorporates a PTFE seal and end plug with O-ring to prevent balance oil pressure leakage.

200, 200C

Pressure Regulator Valve Kit
Part No. 65912-01K

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High-mileage vehicles with a THM 200/200C often experience poor line pressure control due to a worn pressure regulator bore. This can result in high cooler pressure as well as converter and/or friction element failure. The hardened steel valve continuously oscillates within the cast-iron pump bore, resulting in wear. Orificed line/balance pressure is then allowed to leak past the valve and exhaust to the sump. This prevents the pressure regulator valve from staying in its normal regulating position. Sonnax offers a pressure regulator valve kit 65912-01K that eliminates these problems.

  • The Sonnax pressure regulator valve has been modified to incorporate a PTFE seal ring that properly separates the orifice line from the pump suction, preventing cross leakage.
  • The kit includes an O-ringed end plug to assure proper back pressure to the pressure regulator valve.
  • A replacement retaining clip is included.
  • Kit eliminates the need to replace the pump casting to ensure pressure control.
  • Valve
  • PTFE Seal Ring
  • O-Ring
  • nd Plug
  • Retaining Ring
  • 200, 200C Pressure Regulator Valve Kit 65912-01K