Since the first three-speed torque converter automatic from borg-warner in the type 300 C, a lot of progress has been made in the automatic transmission at mercedes-benz so some things done. In the 1990s, for example, there was the NAG (new automatic transmission) or also the FAG (front automatic transmission), which is then replaced by the continuously variable CVT have been replaced.
Since 2003 also the 7G-TRONIC, which is designed for a torque of up to 700 newton meters can be found in numerous mercedes-benz vehicles shifting back and forth between the gears. With the performance daughter AMG on the other hand the powerful AMG SPEEDSHIFT MCT sport transmission.
Also the 7G-DCT, which was introduced in 2011, as well as 9G-TRONIC (since 2013) continue the technological change at daimler.
In the following we take a close look at all newer mercedes automatic transmissions, go to the worst problems and introduce solutions as well as cost of repairs and tips for prevention to.
problems with the 7G-tronic automatic (series W7A) – incl. Costs
The 7G-tronic is a conventional automatic with torque converter, which was the first of its kind to be equipped with 7 driving gears.
This gearbox replaces the outdated mercedes 5-speed automatic and is used in the larger mercedes models with rear- or. all-wheel drive – it is considered to be the typical mercedes automatic transmission.
This is a well-engineered and quite robust design. Installed primarily between 2003 and 2017 and repeatedly improved and revised, the 7G-tronic can be found in the vehicles of the C, E and S-class as well as in various SUV models.
Depending on the engine torque, the version W7A 700 (up to 700 nm) or the W7A 400 (up to 400 nm) installed.
Compared with its predecessor, the 7G-tronic is more economical and, thanks to the magnesium transmission housing, also lighter. The automatic can skip gears when downshifting and has a torque converter bypass with all seven gears. The transmission control is fully electronic, there are no clutches or bands installed.
Basically, the 7G-tronic is a long-life converter automatic transmission. But as with any technical component, problems can occur.
Known are hard, jerky shifting especially with the gears 2, 3 and 4, especially in full-load (kick-down) operation. It is inconvenient, but not dangerous.
Under certain circumstances a new set up of the software eliminate or at least mitigate these problems.
Also, the gear oil level be checked and corrected if necessary. In addition, with old gearboxes the general wear on the converter, the circuit board and the valves after high mileage.
In many cases a gearbox flush and a refill with fresh transmission oil will bring a significant improvement in the complaints when shifting gears (costs in the range of 600 euro). In extreme cases, parts in the gearbox must be replaced or. An overhauled transmission can be installed.
A repair for which you can at any rate count on higher four-digit euro amounts must be.
problems with the 9G-TRONIC automatic (series W9A) – incl. Cost
The 9G-tronic is a further development of the 7G-tronic. As the designation already reveals, this automatic is now equipped with 9 gears and can control torque of up to 700 nm endure.
As with the 7G-tronic, this version will also deliver torque converter used as starting element. The different transmission ratios or. gears are generated, as usual with a torque converter automatic, by a combination of different planetary gears. The transmission control is fully electronic.
Until now this latest mercedes automatic transmission is for no major problems known. As with its predecessor shift jerk and a delayed response to commands cause a certain loss of comfort. Therefore, as with the other automatic transmissions, regular maintenance is the most important precaution for a perfect gearshift feel. This should be every 80.000 kilometers or. To be carried out after 5 years at the latest.
The main reason for shifting problems with the 9G-tronic are again dirt inside the gearbox. Over the years, non-magnetic fin wear (fine dust) is produced which contaminates the transmission oil. Although a part of it is separated by the oil filter, nevertheless the oil becomes increasingly dirtier.
Fine metal abrasion, which also occurs, can be bound with a magnet on the other hand. Not only due to abrasion, but also due to permanent wear, the transmission oil is getting worse and worse.
This can reduce the adhesion between the individual plates, correct shifting is then no longer possible. This is actually already a sign that the maintenance of the 9G-tronic is long overdue.
A professionally performed gearbox flushing, a filter change and a refilling with the correct transmission oil will most likely bring relief.
Here, care should be taken to ensure that the specialist workshop can service and diagnostic equipment specified by mercedes has a number of features, without which proper maintenance is hardly possible. Also always a original-mercedes gearbox oil be filled in, as experience shows that the use of products from the accessories does not always lead to success (even though approved).
With costs an average of 700 euros must be counted for a transmission maintenance on the 9G-TRONIC. This may sound like a lot at first, but over a period of 5 years it is put into perspective again.
With a gearbox service, all problems should be solved in the. If this is not the case, there may be software update to be tried. In extreme cases, components in the transmission are destroyed, resulting in a gearbox exchange is necessary, which is extremely expensive (in the 5-digit euro range).
problems& costs of the DCT (7 and 8 speed) transmissions (724 series)
At the end of 2011, the 7G-DCT automatic transmission of the 724 series was launched on the market, replacing its predecessor, the autotronic CVT transmission. The difference is remarkable, it concerns with the 7G-TRONIC nevertheless a double clutch transmission of most modern type, which makes a sporty and nevertheless economical driving possible owing to the continuous traction.
Since the beginning of 2020, a new 8G-DCT version available, which offers 8 gears. As of 2018, the supplier getrag, which manufactures the DCT versions developed together with mercedes and supplies them to mercedes, also became involved.
As with all dual-clutch transmissions, the DCT functions in such a way that one of the sub-gearboxes always runs while the second remains free, allowing the next gear to be prepared. two oil pumps provide lubrication for the DCT transmission, a fully integrated hydraulic control unit takes care of shifting operations.
The DCT transmissions are used in all mercedes vehicles that are currently based on the compact class platform NGCC (new generation platform) with transversely mounted engine and front or. All-wheel drive stand. These include the A-Class (W176), B-Class (W-246) and the CLA (type 177) and GLA (type X156) series.
Unfortunately, there were and are various problems with all DCT transmissions, which could not be completely solved until today.
While many drivers are very satisfied with their DCT transmission, others complain of Rough gearshifts, hard clicking clutch as well as delayed acceleration. also from jerking and banging noises from the transmission as well as the ignoring of manual gearshifts is reported increasingly.
The solution to this is often software update to. If this does not help, a gearbox flushing lead to success. The costs around 600 euro usually mercedes takes over within the framework of the.
Since the fall of 2020, by the way, a recall is announced by mercedes, because in several recently installed DCT transmissions the oil level is too low can be and thereby problems with the acceleration occur as well as the danger of a transmission damage is given.
As a last possibility (this is often used) only a exchange of the DCT automatic in question. With a complete service book is that with mercedes on guarantee or. goodwill mostly possible without high costs.
A guarantee for the fact that now with the automatic everything is in order, one has thereby however unfortunately not. There are many a DCT driver, who may have under 100.000 kilometers already the third DCT has installed. Therefore, there is actually much to be said in favor of a mercedes-benz with conventional converter automatic (especially 7G-tronic) to reach, as this is much more robust!
problems& cost of automatic transmissions in mercedes-AMG models (speedshift)
It is known that the AMG models from mercedes are equipped with a the most powerful engines the stuttgart based company.
Accordingly, the installed automatic transmissions are largely on the especially high torque adjusted.
In the case of the large sedans and suvs with rear- or. All-wheel drive comes a modified and software-technically improved 9G-tronic to the use, which under the designation AMG speedshift TCT 9G sold.
Under the designation speedshift MCT there will also be an 9G tronic additionally fitted with a wet clutch and racestart function equipped is. Also with these automatic versions the same applies regarding maintenance and faults, which was already mentioned for the "civilian version" in the text above.
With the AMG versions of A-class and CLS- resp. The GLA series, on the other hand, is mostly equipped with the DCT automatic transmission to use. It is sold under the designation AMG speedshift DCT-7G or. Speedshift DCT-8G offered. While the normal 8G-DCT automatic is designed for a maximum torque of 400 nm, the speedshift transmission for the small AMG model can handle up to 520 nm thanks to the overtorque function.
Since the speedshift automatic is largely identical to the normal DCT double clutch transmission, the same problems occur here.
shift jerk, hard clutch engagement and delayed acceleration can significantly reduce the driving pleasure in the AMG. A gearbox flushing and subsequent refilling with the appropriate gearbox oil can often bring relief, a adaptation of the software is another way to eliminate the transmission problems.
In addition, the reinforced DCT automatic transmission in many AMG models of the A-Class, CLS and B-Class (W176, B-Class (W176), CLS and B-Class (B-Class), respectively). GLA series, especially in cold condition, may be in question when shifting from D to R-stage a dull and metallic sounding popping noise to.
This can also be shifting from stage 4 to 3 and from stage 2 to first gear the case a. Who has already experienced this bang, which drives only with an unsafe feeling further.
sometimes an update of the gearshift software can bring improvement – but in most cases the synchronizer rings of the AMG transmission exchanged. This repair takes a few days and can only directly at AMG made.
Therefore, the mercedes dealer removes the DCT automatic and sends it on for repair. Fortunately, mercedes will cover the costs of a complete maintenance booklet within the framework of the warranty or the warranty certificate. Goodwill these high repair costs!
Have you had any experience with defective or problematic Mercedes or AMG transmission versions?? Let us and our readers know in the comments.