6T40 Archives - Transmission Digest
Transtar introduces 6T40 generation 3 shift kit

Transtar’s TransGo brand has introduced a lube boost valve for 6T40 models from model years 2015 to 2022. According to the company, to salvage the pump, TransGo engineered an oversize hardened steel valve and spring combination to minimize the valve oscillation responsible for premature bore wear, ensuring a lasting fix.

Shift pointers: 6T40 neutral drop

A 2011 1.8L Chevy Cruze showed up to the shop with a slipping generation one 6T40 transmission. Engagements were good, but on a quick initial road test it would flare to neutral when the 1-2 shift was commanded. Then it might drop in and hold second gear or shift to third gear and seem okay. 

GM 6T40 Pump Identification Guide

The 6T40 was introduced in 2008 for General Motors front-wheel-drive cars in the Chevrolet Malibu and has gone through several changes throughout its three generations, specifically in the pump area. The 6T40 is closely related to the more lightweight 6T30 and the heavier duty 6T45 and 6T50. Generation one started phasing out during the 2012

GM Gen III 6T40 Pressure Regulator Isolator Valve Kit

GM Gen III vehicles with 6T40 transmissions may exhibit no line rise or low line pressure due to excess wear in the pressure regulator isolator valve assembly. Sonnax has introduced a drop-in pressure regulator isolator valve kit #144510-15K that restores proper line pressure control for renewed shift feel and performance.

GM 6T40/45/50 Bearing Kits

Sonnax has released new GM bearing kits to eliminate bearing noise.

Transmission Tech: Pump Assembly Design

Pumps are important to any automatic transmission, and Mike Riley can give you the details.

Transend Garage 031220 Pumps
Transmission Tech: TEHCM

In this Transmission Tech, learn what separates the 6T40 computer unit from most other transmissions.

Transmission Tech: 6T40 Rotating Clutch Drum

Mike Riley takes some of the conundrum out of the 6T40 rotating clutch drum.

General Motors 9T50 Nine Speed FWD: Part Two

In this continuation from Part One, we’ll be discussing the rotating clutches, planetary gear sets and more on the 9T50.

Is it a Bad Computer?

A 6T40 in a 2011 Chevy Malibu comes in to R.C. Trans and Repair in failsafe with a hard code P0601: Transmission Control Module (TCM) Read Only Memory (ROM). This code is straightforward. Verifying power and grounds to the TECHM are the initial checks to make. Once verified, replacing the computer would be a safe repair. Such was the case with R.C. Trans and Repair.

GM 6T30 Six-Speed Automatic – Junior Addition – Part 2

After General Motors and Ford collaborated on the GM 6T70 and Ford 6F50 transmissions, they recognized the need for another transmission to accommodate lighter-duty vehicles.

GM 6T30 Six-Speed Automatic – Junior Addition – Part 1

During development, the GM 6T70 and Ford 6F50 basically fell off the same sheet of paper resulting in a noticeable amount of interchangeability of various components. One key difference between the two models is that GM chose to go with a mechatronic (TEHCM) valve body design, whereas Ford stuck with the traditional external TCM (PCM). Another variable between the GM and Ford transmissions were the dreaded cushion springs that have been tweaked over the years. Both designs accommodate the larger vehicles equipped with higher output engines and both have received continuous changes and upgrades.