Expertise and repair of the Mercedes C-Class gearbox

The sedan version of the third-generation Mercedes C-Class, the Type W204, already used the 7G Tronic automatic gearbox. When it came out in the 2000s, it was the first mass-market automatic gearbox to offer seven gears! A substantial improvement on the 7G, the 9G Tronic is a nine-speed gearbox designed to optimize performance while reducing fuel consumption.

What are the special features of Mercedes C-Class gearboxes? What to do in the event of a malfunction? Follow the guide EDEN BOITES!

9G Tronic transmission: standard on Type 206

The 9G Tronic gearbox is present on all Type 206 engines, but is also available as an option on older models of the previous generation (Type 205). This is the case, for example, with the C 200 and its M 274 in-line 4-cylinder engine: although an automatic gearbox is available, a six-speed Mercedes 200 Class C 2.2 cdi manual gearbox is standard.

The 9G Tronic considerably improves on the 7G model by offering a more efficient converter: energy losses associated with the use of an automatic gearbox are 15% for the 7G version, compared with just 8% for the 9G. The latter is also more efficient, as gearshifts are less frequent. Clearly, Mercedes is announcing a 6.5% reduction in fuel consumption compared with its previous model!

Mercedes C-Class Type 205: the case of manual gearboxes

Drivers who prefer to have more direct control over their vehicle's gears are not left out, since Mercedes also offers six-speed manual gearboxes, which are fitted to many Type 205 C-Class models.

Mercedes engineers have developed specific gear sets for the engine, enabling it to reach low revs while driving. Special attention is paid to each gear change, thanks to the use of a specific anti-friction lubricant and dry sump lubrication. A friction-reducing internal gearshift also ensures more precise shifting.

What should you do if your gearbox malfunctions?

Whatever the type of gearbox fitted to your Mercedes C-Class, a precise diagnosis of a fault can only be made by a professional mechanic. The gearbox is one of the most complex parts on a vehicle, and it's difficult to pinpoint the precise cause of a problem without the right tools.

Some sources of breakdown can be identified, which will help your mechanic in his research:

• Transmission oil flow is controlled by transmission solenoids, as is gear selector lockout. Difficulty shifting gears or "jumping" gears are two good indicators of a solenoid problem;
• If your vehicle has been driven more than 100,000 kilometers without an oil change, it's time to replace the transmission oil. Otherwise, shifting gears could become difficult, leading to lasting damage to your Mercedes C-Class;
• As the gearbox housing is a closed circuit, it's a good idea to inspect your vehicle regularly for leaks. Identifiable by its brown or dark red appearance, an insufficient level of gearbox oil can destroy your transmission system. In the event of a leak, contact a professional mechanic immediately.

Replacing a faulty gearbox

A gearbox failure does not always mean that the entire gearbox needs to be replaced. Only your mechanic will be able to make an accurate diagnosis.

If you need to make this change, there are several options open to you. You can buy a new box, often at a prohibitive price, or you can go to the second-hand market, without knowing the quality of the product.

A third option is EDEN BOITES. We offer a wide range of standard exchange gearboxes for Mercedes C-Class. Our products are cleaned, tested and completely reassembled. Like new, they even come with a twelve-month warranty! So you get a new gearbox for your vehicle, at used-car prices!

Our advisors are at your service by telephone or via our fast, free online quotation form. So don't wait any longer!