6T40 transmission

Spexcifications

The 6T40 transmission is a GM Hydra-Matic six-speed automatic transaxle engineered for a variety of front-wheel-drive applications. It uses an electronically controlled clutch-to-clutch shifting system to deliver smooth gear changes and consistent performance during every day driving. With six forward speeds and a 0.75:1 sixth-gear overdrive, the 6T40 transmission is designed to provide efficient highway operation while maintaining responsive acceleration. Its 4.58:1 first-gear ratio helps provide strong low-speed performance, while the remaining gear ratios allow the transmission to smoothly transfer power as vehicle speed increases.

The 6T40 transmission was initially designed to handle up to 177 lb-ft. (240 Nm) of torque, while later generations offered increased torque capacity, with some versions rated at up to 277 lb-ft. It uses DEXRON-VI automatic transmission fluid and electronic controls to regulate shift points and overall transmission operation.

Transmission Variants

MH8 6T40 Transmission

The MH8 6T40 is the standard and most commonly used variant of the GM Hydra-Matic 6T40 family. It is designed primarily for front-wheel-drive (FWD) vehicles and features six forward gears, electronic controls, and clutch-to-clutch shifting. The MH8 provides smooth gear changes, responsive acceleration, and efficient highway cruising, making it a suitable transmission for compatible GM passenger vehicles.

MHB 6T40 Transmission

The MHB 6T40 is a variant designed for all-wheel-drive (AWD) applications. It retains the six-speed automatic design and electronic control system of the 6T40 family while being configured for vehicles requiring AWD capability. When replacing an MHB transmission, it is important to match the transmission code and drivetrain configuration to ensure proper compatibility.

MNH 6T40 Transmission

The MNH 6T40 is a Generation 3 version of the 6T40 family, featuring design updates intended to improve efficiency and support modern vehicle technologies. One of its notable updates is an off-axis pump, which allows the transmission to accommodate engine start-stop systems used to reduce fuel consumption. This makes the MNH a more modern version of the 6T40 transmission for compatible applications.

MNK 6T40 Transmission

The MNK 6T40 is another variant associated with Generation 3 6T40 builds. It incorporates the updated design and electronic control technology of the later-generation transmission family. Because transmission specifications and applications can vary by vehicle, engine, and model year, the MNK transmission should be matched using the original transmission code and vehicle application before purchasing a replacement.

Frequently Asked Questions