The 6-speed M20 manual transmission has been produced at General Motors plants since 2004 and is used in Opel Astra, Corsa, and Meriva models with units producing up to 200 Nm of torque. In Fiat, Lancia, and Alfa Romeo vehicles, this transmission is known as the C542.
Specifications
| Type | manual transmission |
| Number of gears | 6 |
| Type of drive | front |
| Engine volume, l | up to 1.8 |
| Torque output, Nm | up to 200 |
| Recommended oil | API GL-4, SAE 75W-85 |
| Oil capacity, liter | 2.4 |
| Replacing the oil | every 60 000 km |
| Replacing the filter | every 60 000 km |
| Gearbox lifespan, km | ~200 000 km |
| Weight, kg | 41 |
Gear ratios Opel M20
Using the 2009 Opel Astra with a 1.3 CDTi engine as an example:
| Main | 3.720 |
| 1st | 4.273 |
| 2nd | 2.158 |
| 3rd | 1.302 |
| 4th | 0.959 |
| 5th | 0.744 |
| 6th | 0.614 |
| Reverse | 3.818 |
Using
The transmission was installed on:
- Alfa Romeo MiTo I (Type 955) in 2008 – 2018
- Fiat Bravo II (198) in 2007 – 2014
- Fiat Doblo II (263) in 2010 – 2020
- Fiat Fiorino III (225) in 2008 – 2016
- Fiat Grande Punto I (199) in 2005 – 2012
- Fiat Linea I (323) in 2007 – 2018
- Opel Astra H (A04) in 2005 – 2010
- Opel Astra J (P10) in 2009 – 2013
- Opel Corsa D (S07) in 2006 – 2014
- Opel Corsa E (X15) in 2014 – 2019
- Opel Meriva A (X03) in 2004 – 2010
- Opel Meriva B (S10) in 2010 – 2017
- Opel Combo D (X12) in 2011 – 2018
Disadvantages of the Opel M20 gearbox
- The main problem with this transmission is the short lifespan of the bearings due to insufficient lubrication;
- Since 2012, a rear cover with larger channels has been installed, and the lifespan has increased;
- On models with powerful engines, the synchronizers in the transmission wear out quickly;
- Many also complain of difficult shifting due to a loose gearshift;
- Another drawback of this manual transmission is the rather expensive dual-mass flywheel.
