722.8

Characteristics of the Mercedes 722.8 Gearbox

The Mercedes 722.8 gearbox is a continuously variable automatic transmission (CVT), also known as Autotronic. It was primarily used in front-wheel-drive models, such as:

• Mercedes-Benz A-Class (W169)
• Mercedes-Benz B-Class (W245)

The design is based on a steel belt (segmental chain) operating between two conical pulleys with variable working diameters. The gear ratio changes smoothly without traditional "gears," resulting in high driving comfort and the absence of perceptible gear shifts.

The 722.8 transmission works with gasoline and diesel engines with moderate torque. It is electronically controlled via a control module integrated with the hydraulics (mechatronics).

Advantages of the 722.8 Gearbox

Smooth Operation

The greatest advantage offered by the Mercedes 722.8 gearbox is an exceptionally smooth ride. The lack of traditional gear shifts eliminates jerking during acceleration.

Comfort in Urban Traffic

In city conditions, the CVT transmission performs very well. The car accelerates evenly, and the controller maintains the engine within the optimal RPM range.

Low Fuel Consumption

When the gearbox is in good working order, it is possible to maintain favorable fuel consumption, as the system selects the ratio so that the engine operates in its most efficient range.

Disadvantages of the 722.8 Gearbox

Limited Durability at High Torque

The CVT does not tolerate aggressive driving or heavy loads. Dynamic starts and frequent driving under full load accelerate the wear of components.

High Repair Costs

Problems with the 722.8 often end in expensive regeneration or component replacement, especially if the belt or conical pulleys are damaged.

Sensitivity to Oil Quality

Maintenance of the 722.8 requires the use of dedicated CVT oil with the correct specification. Service neglect leads to serious damage.

Common 722.8 Faults – Symptoms and Causes

Jerking When Starting

One of the most common 722.8 faults is jerking when pulling away or during maneuvering. This can be caused by a worn drive belt, hydraulic pressure issues, or wear of the starting clutch.

Delayed Throttle Response

If there is a delay between pressing the accelerator pedal and the car's reaction, it is worth checking:

• the condition of the CVT oil,
• gearbox adaptations,
• error codes in the controller.

Computer diagnostics (ideally using Star Diagnosis) allow for reading operating parameters and working pressures.

Limp Mode

Problems with the 722.8 often manifest by the vehicle entering "limp mode." A transmission fault message may appear on the dashboard. Typical causes include:

• a faulty speed sensor,
• mechatronics failure,
• oil overheating.

Oil Leaks

Leaks at the shaft seals or the housing lead to a drop in pressure and accelerated wear of internal components.

How to Prevent Failures – Practical Maintenance of the 722.8

Regular Oil Changes

Although the manufacturer previously suggested long intervals, workshop practice shows that 722.8 service should include an oil and filter change every 50,000–60,000 km.

Avoiding Overloads

It is not recommended to:

• tow heavy trailers,
• start abruptly/rapidly,
• drive for long periods under maximum load.

Regular Diagnostics

In the event of symptoms such as vibrations, slipping, or noise, quick diagnostics of the Mercedes 722.8 gearbox can prevent an expensive repair. Early detection of a hydraulic pressure problem significantly reduces costs.