Sonnax GM 6T30 (Gen. 2) Transmission

Pump

Oversized Pressure Regulator Valve Kit 144510-12K

Helps cure:

Burnt clutches
Erratic line pressure
Low converter & lube flow
Overheating
Poor shift quality
TCC apply & release concerns

Tooling:

F-144510-TL12C
VB-FIX

Oversized TCC Control Valve Kit 144510-05K

Helps cure:

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

Tooling:

F-144510-TL5C
VB-FIX

Valve Body (View Valve Body Layout Diagram)

Actuator Feed Limit Valve Kit 144740-39K

Helps cure:

No 4th
No 5th
No 6th
Low clutch oil pressure
Harsh shifts
Flare shifts

Checkball 10000-08

Imidized Plastic, .250" Dia.

Material: Imidized Plastic
Dia.: 0.250"

Helps cure:

Lost or damaged component

O-Ringed End Plug Kit 144510-14K

Helps cure:

Pressure loss
Burnt clutches
Shift concerns
TCC apply concerns

Oversized Actuator Feed Limit Valve 144740-01

Helps cure:

No 4th
No 5th
No 6th
Low clutch oil pressure
Harsh shifts
Flare shifts

Tooling:

144740-TL

Oversized TCC Regulator Valve Kit 144740-16K

Helps cure:

Code P0741, P0742
No lockup
TCC slip
Loss of fuel economy
Low TCC apply pressure
Overheated fluid & TCC lining
Harsh TCC apply

Tooling:

F-144740-TL16
VB-FIX

Signal Accumulator Piston Kit 144740-40K

Helps cure:

Shift concerns associated with circuit pressure loss
Burnt clutches
Soft shifts

TCC Regulator Valve Kit 144740-38K

Helps cure:

Code P0741, P0742
No lockup
TCC slip
Loss of fuel economy
Low TCC apply pressure
Overheated fluid & TCC lining
Harsh TCC apply

Zip Kit® 6T40-GEN2-3-ZIP

Helps cure:

Burnt clutches
Line pressure instability
Loss of fuel economy
No line rise
Pressure loss
Shift concerns
TCC apply & release concerns
TCC codes

Other

Tool Kit 144740-TL

Tool Kit F-144510-TL12C

Tooling:

VB-FIX

Tool Kit F-144740-TL16

Tooling:

VB-FIX

Tool Kit F-144510-TL5C

Tooling:

VB-FIX

Tech Resources

January 25, 2023

Uncovering the Root Cause of Pressure & Complaints – The Critical Role of Solenoid Modulator & AFL Valves

Maura Stafford

December 29, 2022

Zip Kit FAQ: What's Up with Plugging Separator Plate Ports?

July 01, 2020

Always Identify These Valve Bodies BEFORE You Start a Transmission Rebuild

Andrew Jessiman

June 02, 2017

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

May 25, 2017

GM 6T30/40/45/50 (Gen. 2), 6T35/31/41/46/51 (Gen. 3 6T40) Vacuum Test Guide

September 18, 2014

GM Gen. 1, 2 & 3 6T30, 6T40, 6T45, 6T50 Series Identification Guide

Related Transmission Units

View 6T40 (Gen. 2) Parts View 6T45 (Gen. 2) Parts View 6T50 (Gen. 2) Parts