The General Motors 6L90 (MYD) 6-speed automatic transmission has been produced in USA since 2007 and is installed in the company’s largest models, such as the Chevrolet Suburban, Silverado HD, Express. This transmission is also installed in performance versions of cars, such as the Cadillac CTS-V and Camaro ZL1.
Specifications
| Type | automatic transmission |
| Number of gears | 6 |
| Type of drive | rear / all wheel |
| Engine volume, l | up to 6.6 |
| Torque output, Nm | up to 720 |
| Recommended oil | Dexron VI |
| Oil capacity, liter | 12.3 |
| Partial replacement, liter | 7.0 |
| Maintenance | every 60 000 km |
| Gearbox lifespan, km | ~250 000 km |
| Weight, kg | 111 |
Gear ratios GM 6L90
Using the 2010 Chevrolet Suburban with a 6.0-liter engine as an example:
| Main | 3.73 |
| 1st | 4.027 |
| 2nd | 2.364 |
| 3rd | 1.522 |
| 4th | 1.152 |
| 5th | 0.852 |
| 6th | 0.667 |
| Reverse | 3.064 |
Using
The transmission was installed on:
- Cadillac CTS II (GMX322) in 2008 – 2014;
- Chevrolet Camaro 5 (GMX521) in 2011 – 2015;
- Chevrolet Express 2 (GMT610) in 2010 – …;
- Chevrolet Silverado HD 2 (GMT911) in 2007 – 2015;
- Chevrolet Silverado HD 3 (GMTK2HC) in 2014 – 2019;
- Chevrolet Silverado HD 4 (GMT1HC) in 2019 – …;
- Chevrolet Suburban 10 (GMT931) in 2007 – 2013;
- GMC Savana 2 (GMT610) in 2010 – …;
- GMC Sierra HD 3 (GMT912) in 2007 – 2015;
- GMC Sierra HD 4 (GMTK2HG) in 2014 – 2019;
- GMC Sierra HD 5 (GMT1HG) in 2019 – …;
- GMC Yukon XL 3 (GMT932) in 2007 – 2013.
Disadvantages of the GM 6L90 gearbox
- Most of the problems with this transmission are related to the torque converter in one way or another;
- Not only does it have a weak hub, but the locking clutches also wear out quickly;
- This dirt then clogs the solenoids, reducing the oil pressure in the system;
- Following this chain, the clutches begin to burn out, and even their drums burst;
- Also, the petal-type oil pump does not tolerate long-term driving at high speeds;
- Do not allow the transmission to overheat, otherwise the control unit will simply burn out;
- A common problem with early transmissions was the leaking of the pump cover O-rings.
