Tool Required VB-FIX Required

Printpartsummary
Symptoms:
  • Code P0741, P0742
  • Failsafe mode
  • Harsh shifts
  • Harsh TCC apply
  • High TCC slip RPM
  • Loss of fuel economy
  • Overheated fluid
Cause:

Bore wear at the TCC regulator valve reduces TCC apply and converter charge pressure. A stuck TCC regulator valve causes either TCC slip or harsh apply.

Correction:

Ream to restore the bore and install Sonnax oversized valve kit to restore proper valve function.

Tool Required VB-FIX Required

6L45, 6L50, 6L80, 6L90

Oversized TCC Regulator Valve Kit

Part No.

104740-07K

Oversized TCC Regulator Valve Kit
  • 104740-07k_combo

  • Oversized TCC Regulator Valve Kit

Small_104740-07k_combo Small_104740-07k

6L45, 6L50, 6L80, 6L90

Oversized TCC Regulator Valve Kit

Part No. 104740-07K

  • TCC Regulator Valve
  • Shuttle Valve
  • End Plug

Complaint:

  • Code P0741, P0742
  • Failsafe mode
  • Harsh shifts
  • Harsh TCC apply
  • High TCC slip RPM
  • Loss of fuel economy
  • Overheated fluid

Cause:

Bore wear at the TCC regulator valve reduces TCC apply and converter charge pressure. A stuck TCC regulator valve causes either TCC slip or harsh apply.


Correction:

Ream to restore the bore and install Sonnax oversized valve kit to restore proper valve function.

Vehicles with GM 6L45, 6L50, 6L80, 6L90 series transmissions may have a number of TCC apply problems. Bore wear at the TCC regulator valve can cause no TCC apply or slipping on engagement, harsh shifts, loss of performance and fuel economy, and fluid overheat. If the valve is stuck in the apply position, the result is harsh TCC apply. If the valve is stuck in the release position, no TCC apply or TCC slip will result. Installing Sonnax oversized TCC regulator valve kit 104740-07K will restore proper valve function, resulting in proper TCC apply.

  • Valve is hardcoat anodized to reduce wear
  • Restores proper valve function and TCC apply

Required Tools

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.

  • Test Locations

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Valve Body Layouts

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.

Valve Body Layout GM 6L45, 6L50, 6L80, 6L90

Related Tech Articles

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GM 6L45-6L90 Vacuum Test Guide

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