The 6T70 transmission was introduced by General Motors in 2007. It is a fully-automatic six-speed transmission. The GM 6T70 was preceded in engineering design by the 6T40, 6T45, and followed by the 6T80 transmission. The 6T70 is manufactured for front-wheel-drive and all-wheel-drive vehicles.

Originally, the 6T70 was made for use with 3.6-liter V-6 engines. It was initially installed in GMC’s Acadia, its Saturn Aura, and its Pontiac G6 (while GMC was still making Pontiacs). The 6T70 was the proud product of one of the several design collaborations between GM and Ford in the early 2000s. The GM 6T70s were also built for installation in the Chevy Impala, Equinox, and Malibu. This transmission was also used on the GM truck production lines in the Saturn Outlook and Buick Enclave. (GM transmission codes that you may see used to identify the 6T70 include MH2, MH4, M7U, M7V, M7W, and M7X.)

The 6T70 transmission is electronically controlled, offering vehicle owners the benefit of increased reliability from advanced technology. The Transmission Control Module (TCM) inside the transmission enables fully automatic changing of gear ratios.

Other automatic transmission designs employ a different coupling arrangement for accelerating at lower speeds, whereas the GM Hydra-Matic design of the 6T70 utilizes four speeds for forward acceleration instead.

An array of electronic sensor inputs are monitored by the 6T70 Transmission Control Module (TCM). The TCM receives and applies the collective information inputs to determine the ideal point in the process at which the gear shifting is automatically executed. It sends commands to the transmission system’s clutch pressure control solenoid and shift solenoid to precisely manage shift timing. The 6T70 TCM further manages the torque conversion clutch, enabling greater fuel efficiency from the engine while maintaining vehicle performance.

The 6T75, not to be confused with the 6T75 transmission, is a slightly larger and otherwise modified design. The 6T70 is designed to aid in maximizing a vehicle’s fuel efficiency, smoothness in automatic gear shifting, and overall optimal transmission performance. For example, the ratio spread in the gears is high, especially in first gear, which means more robust acceleration from a stopping position. The highest gear is overdrive, to minimize engine friction and maximize fuel savings during highway driving.

Unlike other GM transmission designs, the 6T70 gearing is all aligned with the centerline of the engine. This offers the benefits of increased interior space and reduced height of the powertrain.

Advanced functions of the 6T70 transmission facilitate smoother shifting. The electronic gear shifting controls in the 6T70 provide the same accuracy in timing the automatic gear shifting as comparable transmission designs. But, the clutch-to-clutch precision auto-shifting design of gears 2 through 6 in the 6T70 saves space in the unit design compared to models without this feature. Adaptive controls over automatic shifting account for braking on variable grades, prompting the transmission to maintain lower gears during deceleration or on declining grades. This minimizes the need for braking in many circumstances and prevents inappropriate automatic acceleration.

The smaller size of the 6T70 makes it ideal in the smaller vehicles for which it was designed, and it presents a broader range of options for safety designs and aesthetic styling of new models. Other beneficial features of the 6T70 include its hydraulic pressure feature for minimizing the transmission’s energy requirements and overall vehicle fuel efficiency.

The 6T70 transmission came in the Buick LaCrosse, Buick Enclave, Pontiac Torrent, Pontiac G6, Saturn Outlook, Saturn Aura, Cadillac SRX, Cadillac XTS, Chevrolet Equinox, Chevrolet Malibu, GMC Acadia, and GMC Terrain.