Mercedes uses a number of different gearboxes in their vehicles, ranging from several different manual gearboxes, to torque-converter automatics in the form of their G-Tronic gearboxes with 4, 5, 7 or 9 gears depending on the generation, used in many of their vehicles for almost 30 years, to dual-clutch applications in some recent models, to beastly AMG Speedshift with either multi-clutch (MCT version) or torque converter, to even CVT in some B-Class models.
Unlike most other manufacturers, Mercedes-Benz is known for developing their own gearboxes and pairing them perfectly with their engines. This perfected setup ensures smooth shifts, plenty of torque, timely shifts and confident power buildup.
Even though the previously mentioned kinds of gearboxes have very different ways they work, there is one thing that is common for all of them – they are all controlled by TCUs (Transmission Control Unit). This means that an adjustment in softwares of these control units can change the way gearboxes work.
This way we can affect shift times and speed, torque limits, shifting smoothness, launch control settings and more.
Before that, let’s see how these different gearboxes work in short and what are the advantages and disadvantages of each of the systems.
Torque Converter Automatic Gearboxes (G-Tronic)
This is the most common kind of automatic. Gear ratios are changed using planetary gearsets and their smoothness, as well as torque multiplication, is facilitated by a torque converter. The torque converter uses liquid to transfer force, so there are some loses, before it locks up to match the turning of the crankshaft.
Use of the liquid enables impeccably smooth shifts and even power delivery, which makes torque converter automatics a great mix of comfort, smoothness and driving feel. This makes them the best choice for most of the vehicles on the roads nowadays and it is the reason why torque converter automatics are the most common kind of gearbox in the industry.
AMG Speedshift is a more hardcore version of the G-Tronic developed for high-powered AMG vehicles. Depending on the kind, AMG Speedshift either has a multi-clutch setup (MCT) with wet start-off clutch, or torque converter.
Dual-Clutch Gearbox (7G-DCT)
Dual-clutch gearbox is basically an automated mixture of two manual gearboxes. The two clutches are used to shift gears in a way that one clutch is used to control odd gears (1, 3, 5 and 7 in the 7G-DCT) and the other one to control even gears (2, 4 and 6).
This means that while one clutch is engaged the second one can prepare the next gear. Once the shift is supposed to happen, the first clutch disengages and the second one engages giving a shift that is next to instant.
This makes DCT gearboxes lightning fast and often used in sports cars, but also in other vehicles. This also means there is no liquid-based force transfer, so there are no loses of this kind.
Continuously variable transmission enables a change in the output speed even when the input speed remains constant. This means that it can keep the engine it its most comfortable and efficient speed, while changing speed at the wheels.
This greatly improves efficiency, but it also gives a bit of unnatural driving feel, since the sound of the engine does not always match the change of speed. For example, the engine can sit at 3,000 rpm while the speed of the vehicle increases.
Each of these systems has advantages and disadvantages. For example, DCT gearboxes are very fast, but they can be jerky at small speeds, or less comfortable if the computer anticipates the wrong gear.
Moreover, they are designed opposite from what some of our customers want. For example, torque limits may be too conservative, shift times for torque converter automatics can be slower than the customer wants, or shifting points may be different from the desired.
We can adjust this and make your gearbox work just the way you like it. Here are just some of the gearbox tuning services:
We can change the shit points to suit your driving style and thus prevent keeping the revs too low below the turbo spooling point, or too high making fuel consumption worse.
Here we adjust the inbuilt delays in shift times in order to improve acceleration.
Launch control is a mixture of features that are designed to give you the fastest time off the mark. However, sometimes we can adjust these features to give you even faster launches. For example, one of the features is limiting revs at a certain point to reduce wheel spin. This is often set too low and we can adjust it.
This is especially useful on DCT and torque converter automatics after tuning. We can increase torque limits to allow more torque sent to the wheels, but also always keep the gearbox safe.
While explaining the advantages and disadvantages of the DCT gearbox, we spoke about how jerky it can be sometimes. We can adjust shift smoothness for DCT gearbox and make it much more enjoyable in everyday driving while preserving its ruthlessness in sporty and racing applications.