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  • Burnt clutches
  • Pressure loss
  • Shift concerns
  • TCC apply concerns


End plug wear allows valuable actuator/solenoid feed pressure to leak at the various regulator valve bores. When the clutch select valve end plug leaks, Reverse pressure suffers.


Recover hydraulic control and renew critical circuit pressures by installing Sonnax O-ringed end plug kit.

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

O-Ringed End Plug Kit
Part No. 144740-02K

You need this if... View Instructions

OE end plugs are designed to prevent critical pressure loss by capping the bore, while also functioning as a spring or valve stop. Repetitive spring motion, valve impact and fluid pressure variations cause wear between the end plug and bore mating surface, allowing vital pressure to escape the circuit.

GM first generation 6T40, 6T45, and 6T50 valve bodies have end plugs at the various clutch regulator valve bores which are susceptible to this wear. When actuator/solenoid feed pressure is allowed to leak due to plug deterioration, various shift concerns and burnt clutches will result in the affected circuit. Wear at the TCC regulator and clutch select valve end plugs allows valuable oil loss that leads to drivability concerns. Correct leackage and restore hydraulic integrity by installing Sonnax O-ringed end plug kit 144740-02K.

  • Minimal end-plug-to-bore clearance with added O-ring for positive seal
  • No reaming or special tools required
  • End Plugs (6)
  • O-Rings (9) 3 extra

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

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

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  • 144740 02k combo
  • 144740 02k

You need this if...

Vacuum tests at the ports indicated fail to hold the recommended minimum 18 in-Hg.

  • 144740 02k in test