Symptoms:

  • Code P0741
  • Code 742
  • No lockup
  • TCC slip
  • Loss of fuel economy
  • Low TCC apply pressure
  • Overheated fluid & TCC lining
  • Harsh TCC apply

Cause:

Bore wear at the TCC regulator valve reduces TCC apply and converter charge pressure. If valve sticks, TCC slip or harsh apply will result.

Correction:

Recover hydraulic control and renew TCC performance by reconditioning the bore and installing Sonnax oversized TCC regulator valve kit.

6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40)

Oversized TCC Regulator Valve Kit
Part No. 144740-16K


You need this if... View Instructions Find a Distributor

Vehicles equipped with 6T30/40/45/50 (Gen. 1 and 2) and 6T35/31/41/46/51 (Gen. 3 6T40) transmissions can exhibit a number of TCC apply issues caused by bore wear at the TCC regulator valve. Slipping TCC, no TCC apply, fluid overheat and suffering fuel economy are common results of this wear. If the valve becomes stuck in the apply position, harsh TCC apply will be the consequence. If the valve is stuck in the release position, no TCC apply or TCC slip will occur. Installing Sonnax oversized TCC regulator valve kit 144740-16K re-establishes correct valve-to-bore clearances, restoring normal TCC operation.

  • Lengthened spools for additional bore contact and support
  • Hardcoat anodized aluminum valves combat premature wear
  • Annular grooves help center valves in bore to reduce future side-load wear
  • Shuttle Valve
  • End Plug
  • Spring
  • O-ring
  • Regulator Valve

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 Gen. 1 6T40, 6T45, 6T50 Valve Body Layout

GM Gen. 1 6T40, 6T45, 6T50 Valve Body Layout

GM Gen. 2 6T30/40/45/50, Gen. 3 6T40 Valve Body Layout

GM Gen. 2 6T30/40/45/50, Gen. 3 6T40 Valve Body Layout
  • 6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Oversized TCC Regulator Valve Kit 144740-16K
  • 6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Oversized TCC Regulator Valve Kit 144740-16K

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.

6T30 (Gen. 1), 6T30 (Gen. 2), 6T31 (Gen. 3 6T40), 6T35 (Gen. 3 6T40), 6T40 (Gen. 1), 6T40 (Gen. 2), 6T41 (Gen. 3 6T40), 6T45 (Gen. 1), 6T45 (Gen. 2), 6T46 (Gen. 3 6T40), 6T50 (Gen. 1), 6T50 (Gen. 2), 6T51 (Gen. 3 6T40) Oversized TCC Regulator Valve Kit Vacuum Test Locations