Analyzing the 9G Tronic Transmission: Is it Better than its 7G Predecessor?

By  //  March 31, 2022

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Mercedes presented to the world the first-ever 9-speed automatic gearbox designed for the premium vehicles, and it was a good few months in front of Range Rover. Called 9G Tronic, the new gearbox is set to temporarily replace the 7G Tronic. On being unveiled, it debuted on the E 350 Blue Tec model and was also mounted on four other versions of CLS facelift. Also, it is set to be installed in other E-Class versions, ML, C, S, and the next GLK. 

So, in what ways is the 9G transmission better than its predecessor? Is it more fuel-efficient and more comfortable? In this article, we look at what new features this latest 9-speed transmission adds to Mercedes Benz. Read on to learn more. 

What do the additional two gears mean?

The extra two gears contribute directly to the efficiency of the new gearbox. That is because; the difference in the ratio of the distance between the 1st and the 9th gear is 9.15. This makes it a vital part concerning efficiency. Therefore, the E 350 Blue Tec can attain higher speeds at exceptionally low revs.

This means that you can, for example, cruise at a speed of 120km/h at only 1350 revolutions per minute (rpm). Additionally, the maximum speed of Blue the E 350 Blue Tec is 250km/h and this can be reached when the rev count is only 2700 rpm. 

For comparison purposes, in Audi and BMW, the difference in the ratio of the distance from the 1st and the eighth gear is about 8 or 7. This means that when they hit maximum speeds, the 6-cylinder diesel engines from Audi and BMW rotate at greater revs with 500 or higher rpm when they hit the top of their transmission.

Mercedes Benz also promises incredibly modest fuel consumption for its 9G Tronic debutant of just 5.3l/100km. The CO2 emission is also relatively lower at just 138g/km. 

But the long-distance in the ratio between the 1st and the 9th gear is not just advantageous in the efficiency but also increases driving comfort. In theory, considering the massive torque of 620Nm of a 3-liter diesel at 1600 rpm, a Mercedes engine does quite well with just three or four gears. If you factor in the 9 gears, it becomes apparent that it offers even more driving comfort and refinement.

Lightweight

Do not be fooled by the extra two gears and a maximum 1000 Nm transferrable torque of the 9G Tronic. The truth is that this new transmission takes less space compared to the 7G Tronic that it replaced. Additionally, this transmission system is also lighter, weighing less than 100 kg. The casing of the gear comprises two components.

The first one is the aluminum casing that houses the torque converter. The other housing is for the transmission and it’s made of magnesium alloy. At the same time, the manufacturer uses plastic to make the sump. Although there are two extra gears, the nine-speed transmission also contains four semi-axle & six shift elements as opposed to the five which is what’s contained in the 7G Tronic.

Comes with two Pumps

Another significant upgrade in the 9g Tronic is the size of the pumps. The main pump, which is way smaller compared to the previous one, is now positioned next to the primary axle. It is also chain-driven and not directly driven, and is operated by a pump that’s auxiliary powered.

This makes it easy to control the cooling and lubrication upon request, with the main aim being to be familiarized with the start-stop system. And because of the enhanced hydraulic torque converter, transmission efficiency is increased to 92%. This reduces the transfer loss between the engine and the torque and the transmission shaft. 

The gearbox, just like the 7g Tronic Plus, has three modes namely Sport, Manual, and Economy. There is also another temporary one called M mode. This can only be enabled on the Economy and Sport modes upon engaging certain gears using paddle shifters. The mode remains active when changing the gears manually, or if a sporty driving style is maintained. This is completely different from the long-term Manual mode, which is available together with the AMG Line package.

How to Keep Your Transmission Working at its Peak

The automatic transmission in any car is expensive. The 9G Tronic is even more costly. Replacing it can be even more costlier than overhauling the engine. That’s why you must take proper care of your automatic transmission to prevent these costly repairs or replacements. Here are a few things you can do to prevent premature breakdowns of your transmission and extend its life:

Understand your service schedule

The first thing you need to do is to know when the service is due. Different models of Mercedes Benz will have varying transmission service recommendations. The initial service suggestion in most models is after 40,000 miles. If you are unsure, talk this up with your mechanic.

Always insist on an approved mechanic

Any mechanic out there will claim to be the best, so the task is to find an authorized Mercedes mechanic. An approved mechanic will guarantee their services and are often more knowledgeable in fixing these intricate pieces of precession engineering.  

Regularly change the Transmission Oil

The one mistake you don’t want to make is not changing the transmission fluid as regularly as the manufacturer recommends. Transmission fluid is what lubricates the moving parts of the automatic transmission. Check your manual to know how frequently it should be changed. 

 Additionally, you need to know signs that your transmission has malfunctioned. These include strange clunking noise, failure of the unit to respond when you press the gas with your foot, engine revs even if not provoked, the car refusing to accelerate, among other things. If you notice things like these, the best thing is to have a mechanic check it up. Early detection can be the difference between cheap and costly transmission repair.  

Conclusion

The 9G Tronic is an improved 7G Tronic automatic transmission. It improves almost every aspect of the older version, like comfort and fuel efficiency. Additionally, the later model is lighter than the 7G Tronic version, despite having two extra gears.