Gearbox Mercedes 7G-DCT (724.0)

The 7-speed robotic gearbox 724.0 or Mercedes 7G-DCT has been produced since 2011 and is installed on almost all front-wheel drive models of the concern, such as the A-Class and B-Class. This preselective robotic gearbox was created together with Getrag and has a lot in common with the 7DCT300.

This series includes: 7G-DCT, AMG SpeedShift DCT, 8G-DCT.

In 2011, for front-wheel drive cars on the MFA platform with transverse engines, a new seven-speed preselective robotic gearbox with two wet clutches was created. This gearbox was combined with gasoline and diesel engines with up to 350 Nm of torque, and it was also possible to connect the proprietary 4Matic all-wheel drive through a gearbox. The gearbox was designed together with Getrag engineers and served as the basis for the 7DCT300.

Among the design features, we note the presence of an additional electric oil pump, as well as an electric pump for supplying coolant from the reservoir to the gearbox heat exchanger. There are front-wheel drive modifications of the robotic gearbox K7A240, K7A350 and all-wheel drive K7X350, plus a reinforced modification with the index K7X400 was created specifically for AMG versions.

Specifications

Production years since 2011
Type preselective robotic transmission
Number of gears 7
Type of drive front / all wheel
Engine volume, l up to 2.1
Torque output, Nm up to 350 (in the enhanced AMG version up to 475 Nm)
Recommended oil MB 236.21
Oil capacity, liter 7.5
Replacing the oil every 60,000 km
Replacing the filter every 60,000 km
Gearbox lifespan, km ~300 000
Weight, kg 86

Gear ratios Mercedes 7G-DCT

Using the example of a Mercedes A-Class 2020 with a 2.0 liter engine:

Main 4.130
1st 3.857
2nd 2.429
3rd 1.536
4th 1.049
5th 0.776
6th 0.604
7th 0.480
Reverse 3.375

The transmission was installed on:

  • Infiniti Q30 1 (H15) in 2015 – 2019;
  • Infiniti QX30 1 (H15) in 2016 – 2019;
  • Mercedes A-Class W176 in 2012 – 2018; A-Class W177 since 2018;
  • Mercedes B-Class W246 in 2011 – 2019; B-Class W247 since 2019;
  • Mercedes CLA-Class C117 in 2013 – 2019; CLA-Class C118 since 2019;
  • Mercedes GLA-Class X156 in 2013 – 2019; GLA-Class H247 since 2019;
  • Mercedes GLB-Class X247 since 2019.

Disadvantages of the Mercedes 724.0 gearbox

  • In the first years of production, the robotic gearbox often bothered with jolts and jerks when switching, and new firmware usually helped, but sometimes the control unit had to be replaced. There were cases of rapid wear of the fork tips and failure of the electric oil pump.
  • Nowadays, most of the problems with this transmission are somehow related to the mechatronics, so change the lubricant as often as possible or the valve body solenoids will not last long.
  • Driving with faulty mechatronics greatly reduces the life of the double clutch unit.
  • The mechanical part of the gearbox is very reliable and breakdowns occur over long runs. Most often, owners replace synchronizers, as well as differential bearings.

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