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  • Excess TCC slip
  • Low converter & lube flow
  • Low cooler flow
  • Overheating
  • TCC apply & release concerns
  • TCC codes
  • TCC lining failure


Wear of the TCC control valve bore due to continuous valve oscillation causes multiple TCC and lube/cooler circuit concerns.


Recover hydraulic control and restore proper TCC apply/release and cooling circuit operation by installing Sonnax oversized TCC control valve kit.

6T30, 6T40 (Gen. 1), 6T40 (Gen. 2), 6T45 (Gen. 2), 6T45 (Gen.1), 6T50 (Gen. 1), 6T50 (Gen. 2)

Oversized TCC Control Valve Kit
Part No. 144510-05K

You need this if... View Instructions

Common concerns associated with listed GM transmissions are TCC slip, TCC lining degradation, TCC slip codes, and converter apply or release issues. These problems are often caused by excess wear at the TCC control valve bore. In addition, converter/lube and cooler flow can be restricted, resulting in an overheat situation.

Reconditioning the bore and installing Sonnax oversized TCC control valve kit 144510-05K restores hydraulic integrity for renewed TCC, lubrication and cooler operation. Hardcoat anodized aluminum valve combats premature wear.

Proper TCC control relies on correct line pressure; if line pressure problems are discovered, Sonnax offers oversized pressure regulator valve kit 144510-01K.

Prior to reaming TCC control valve bore, a 1/2" spacer plate must be inserted between pump and VB-FIX. See instructions for details.

  • Valve
  • Spring

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

Gm 6t40 gen1 vbl thumb

GM 6T30 & 6T40, 6T45, 6T50 (Gen. 2) Valve Body Layout

6t40 gen2 vbl thumb

October 31, 2014

GM 1st Gen. 6T40, 6T45, 6T50 Vacuum Test Guide

Topics: Vacuum Test Guides Vacuum Testing Transmission GM 6T45 (Gen.1) Transmission 6T50 (Gen. 1) Transmission 6T40 (Gen. 1) Transmission

Read Now

September 30, 2005

Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits

Gregg Nader

Topics: Diagnostics And Theory Transmission

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May 25, 2017

GM 6T30 & 6T40, 6T45, 6T50 (Gen. 2) Vacuum Test Guide

Topics: Vacuum Test Guides Transmission GM 6T40 (Gen. 2) Transmission 6T45 (Gen. 2) Transmission 6T50 (Gen. 2) Transmission 6T30 Transmission

Read Now
  • 144510 05k combo
  • 144510 05k

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.

  • 144510 05k test