Tool Required

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Symptoms:
  • Erratic TCC apply
  • Failsafe mode
  • Harsh shifts
  • Pressure control out-of-range codes
  • Shift codes
  • Slips, flares & bind-ups
  • Switch codes
Cause:

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

Correction:

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

Video Tool Required

6L45, 6L50, 6L80, 6L90, 6T70 (Gen. 1), 6T75 (Gen. 1)

Pressure Switch Rebuild Kit

Part No.

124740-30K

Pressure Switch Rebuild Kit
  • Pressure Switch Rebuild Kit

Small_124740-30k

6L45, 6L50, 6L80, 6L90, 6T70 (Gen. 1), 6T75 (Gen. 1)

Pressure Switch Rebuild Kit

Part No. 124740-30K

  • Laminate Discs (5) 1 Extra
  • Seals (5) 1 Extra

Complaint:

  • Erratic TCC apply
  • Failsafe mode
  • Harsh shifts
  • Pressure control out-of-range codes
  • Shift codes
  • Slips, flares & bind-ups
  • Switch codes

Cause:

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


Correction:

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

Listed GM 6-speed 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 TCC apply problems or 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 124740-30K restores normal switch operation, eliminating codes and providing renewed shift performance in all ranges.

  • Allows salvage of expensive TEHCM
NOTE:

Before installing kit, test switches to verify proper electrical operation. Kit repairs laminate disc and seal failures only; it will not rectify electrical breakdown. See instructions for details.

Related Parts

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Easy Pressure Switch Rebuilds for 6L- & Gen. 1 6T-Series Units

GM 6-speed transmissions often set various trouble codes caused by fluid pressure switch failure. Replacement of the expensive TEHCM in which the switches live was traditionally the only way to restore normal shift operation, but now there’s a better alternative: rebuilding the switches.

Sonnax's patent-pending rebuild kits for 6L-series and Gen. 1 6T70, 6T75 units contain exactly the right tools and parts for fast, safe installation of new pressure switch laminate discs and seals. There’s no coaxing, no practice, just successful switch rebuilds the first time, every time.

Watch the video to learn how this simple, affordable technique will save you hundreds of dollars and keep the TEHCM out of the boneyard!

Contact a Sonnax Distributor to purchase this part.