The General Motors 6T30 6-speed automatic transmission, in its MH9 modification, has been produced since 2008 and is installed in smaller models with low-power engines up to 1.8 liters. In some markets, this automatic transmission is best known as the transmission in the Chevrolet Cruze, Sonic, and Cobalt.
Specifications
| Type | automatic transmission |
| Number of gears | 6 |
| Type of drive | front |
| Engine volume, l | up to 1.8 |
| Torque output, Nm | up to 175 |
| Recommended oil | DEXRON VI |
| Oil capacity, liter | 7.6 |
| Partial replacement, liter | 4.5 |
| Maintenance | every 60 000 km |
| Gearbox lifespan, km | ~250 000 km |
| Weight, kg | 71.5 |
In 2008, GM introduced a slightly simplified version of the 6T40, the 6T30, which is installed on front-wheel-drive vehicles with engines producing up to 175 Nm of torque. This is a standard hydromechanical automatic transmission for models with a transversely mounted unit, designed according to a typical American design, where the transmission output shaft is driven by a chain.
Gear ratios GM 6T30
Using the 2012 Chevrolet Cruze with a 1.6-liter engine as an example:
| Main | 4.11 |
| 1st | 4.449 |
| 2nd | 2.908 |
| 3rd | 1.893 |
| 4th | 1.446 |
| 5th | 1.000 |
| 6th | 0.742 |
| Reverse | 2.871 |
Using
The transmission was installed on:
- Chevrolet Aveo 2 (T300) in 2011 – 2019;
- Chevrolet Cobalt 2 (T250) in 2013 – …;
- Chevrolet Cruze 1 (J300) in 2008 – 2016;
- Chevrolet Sonic 1 (T300) in 2011 – 2018;
- Daewoo Gentra 2 (J200) in 2013 – 2015;
- Opel Corsa E (X15) in 2014 – 2019;
- Ravon Gentra 1 (J200) in 2015 – 2018;
- Ravon Nexia 1 (T250) in 2016 – 2018.
Disadvantages of the GM 6T30 gearbox
- The most notorious weak point of this transmission is the spring disc of the 3-5-R drum, which simply breaks, then breaks the locking mechanism, and debris flies throughout the transmission system. The automatic transmission has been upgraded several times, but the problem has not been completely eliminated.
- The second most common problem for service centers is the replacement of solenoids. They are very sensitive to dirty oil and often fail before 100,000 km. The main culprit is considered to be overly aggressive settings of the transmission control unit.
- Service technicians also note the limited life of the sliding bushings, a weak differential, rapid contamination of the speed sensors, and an insufficient standard cooling system.
