This GM 6T30/6T40/6T45/6T50 TechTran Manual contains the procedures necessary to diagnose, overhaul and/or repair the 6T30/40/45/50 (6 Speed) GEN 1, GEN 2 & GEN 3 (supplement provided) transmissions from General Motors.
The Hydra-matic 6T30/40/45/50 (6 Speed) is a fully automatic, six speed, front wheel drive, electronically controlled transmission that features clutch to clutch shifting. It is also all-wheel drive capable. It was first introduced in the 2007 Chevy Captiva followed by the Malibu in 2008 and quicky spread to the compact, mid-size, small crossover vehicle line, as shown in Figure 1. The 6T40 is also found in hybrid applications. At the start of production for the 2012 model year Generation 2 was introduced which is currently used in all platforms using the 6T family of transmissions. This series of transmissions is also known as the GF6. In 2015, Generation 3 was introduced and is covered in the manual per the supplement included inside this manual.
It consists primarily of a four element torque converter, three planetary gear sets, five clutch packs, one mechanical one-way clutch and a hydraulic pressurization and control system. Three planetary gear sets provide the six forward gear ratios and reverse. Changing gear ratios is fully automatic and is accomplished through the use of a Transmission Control Module (TCM), that is located within the transmission. The TCM receives and monitors various electronic sensor inputs, and uses this information to shift the transmission at the optimum time. The TCM commands shift solenoids and Clutch Pressure Control (CPC) solenoids within the transmission to control shift timing. The TCM controls shift feel through the CPC solenoids. The TCM also controls the apply and release of the torque converter clutch which allows the engine to deliver the maximum fuel efficiency without sacrificing vehicle performance. This manual contains the procedures necessary to diagnose, overhaul and/or repair the 6T30/40/45/50 (6 Speed) GEN 1 and GEN 2 transmissions from General Motors and is for use by professional technicians.