• Pressure switch codes
  • Pressure control out-of-range codes
  • Failsafe mode
  • Slips, flares & bind-ups
  • Harsh shifts
  • Shift codes


OE pressure switch laminate disc breached, preventing proper switch operation.


Salvage the transmission control unit and restore normal shift operation by installing Sonnax pressure switch rebuild kit.

6T30 (Gen. 1), 6T40 (Gen. 1), 6T45 (Gen. 1), 6T50 (Gen. 1)

Pressure Switch Rebuild Kit
Part No. 144510-09K

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GM Gen. 1 6T30/40/45/50 transmissions often set various trouble codes related to failures of fluid pressure switches that are internal to the transmission electro-hydraulic control module (TEHCM). These codes may be accompanied by shift irregularities such as slipping, flares, harsh application and bind-ups. As time goes by, the laminated portions of the pressure switches can breach, preventing normal switch operation. If more than one switch breaks down, failsafe mode can be triggered. Since switches cannot be obtained through OE channels, replacement of the TEHCM was the only previous remedy available.

It is no longer necessary to replace the expensive TEHCM assembly to rectify this concern. Installing Sonnax pressure switch rebuild kit 144510-09K restores normal switch operation, eliminating codes and providing renewed shift performance.

  • Allows salvage of TEHCM
  • No special tools necessary
  • O-Rings (4)
  • Laminate Discs (4)
  • Spacers (4)
  • D-Rings (4)

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

GM 6T30/40/45/50 (Gen. 1) Valve Body Layout

GM 6T30/40/45/50 (Gen. 1) Valve Body Layout

  • 6T30 (Gen. 1), 6T40 (Gen. 1), 6T45 (Gen. 1), 6T50 (Gen. 1) Pressure Switch Rebuild Kit 144510-09K