BMW 5 Series E39 520i M52 Automatic Auto Gearbox A5S310Z 1422855 WARRANTY

BMW 5 Series E39 520i M52 Automatic Auto Gearbox is an original drivetrain component designed for models with the M52 engine and automatic transmission. Engineered by BMW, the A5S310Z transmission ensures smooth gear shifting and full compatibility with the vehicle's factory electronics. This is a used component that allows for a technically correct replacement of a faulty gearbox in your E39.

Specifications and technical data

• SKU: 1422856
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 1422855
• Substitutable numbers: 24001422856, 1422856, 24001422855 24001422027 24001422026, 1422855 1422027 1422026
• Gearbox type: Automatic
• Category: Other Transmission & Drivetrain

Purpose and compatibility

The presented automatic transmission is dedicated to the BMW 5 Series E39 520i with the M52 engine, equipped with an automatic gearbox. The A5S310Z design was developed specifically for the torque characteristics of the M52 unit, which translates into predictable vehicle behavior in city traffic and on the highway.

Selecting this gearbox for a specific vehicle allows for factory-level integration with the drivetrain, engine control unit, and transmission control modules. This ensures consistent operation of the entire system without the need for aftermarket solutions or non-factory adaptations.

Construction and operating characteristics

The A5S310Z automatic transmission belongs to the classic BMW torque converter automatic gearboxes, where the priority is operational stability and predictable gear shifting. The applied gear ratio configuration has been selected to:

• ensure smooth starting and acceleration under typical road conditions,
• maintain optimal M52 engine RPM within the economical driving range,
• reduce jerking during gear changes, especially in city traffic.

Thanks to the factory BMW design, the gearbox communicates with the engine management system, which allows the shift points to be adjusted to the current load and the driver's driving style.

Application in service practice

Replacing the automatic transmission in a BMW E39 520i with an M52 engine is often necessary when symptoms such as noticeable jerking, delayed gear engagement, or starting issues occur. Using a used A5S310Z transmission allows for restoring proper drivetrain operation while maintaining factory specifications. This is a particularly beneficial solution for cars used daily, where functionality and compliance with the original design are essential.

Before installation, standard service procedures are recommended, including checking the transmission oil cooling system, verifying the condition of the mounting bushings, and inspecting the electrical wiring controlling the transmission. This approach minimizes the risk of repeated disassembly and reduces vehicle downtime.

Benefits of choosing an original BMW gearbox

By choosing an original BMW automatic transmission, you gain a component designed exactly for your model, without the compromises typical of universal solutions. Key advantages include:

• factory fitment for the M52 engine and vehicle electronics,
• consistent gear shifting characteristics in line with the manufacturer's specifications,
• the ability to retain original transmission operating modes (e.g., comfort and dynamic, if present in the car's configuration),
• easier diagnostics using factory BMW service tools.

For users who value predictability and compliance with the manufacturer's service documentation, this choice is particularly rational.

Condition and verification of fitment

The offered gearbox is a used component, which is a frequently chosen solution in BMW service practice for repairs of older generations, such as the E39. Before purchasing, it is worth verifying the compatibility of the transmission with your specific car configuration using the OEM part number and available interchangeable numbers in the technical specifications section. This helps to reduce the risk of mechanical or electronic incompatibility.

In the case of installation at a specialized service center, it is also possible to perform a transmission adaptation using appropriate diagnostic software, which helps to optimize its operation after replacement.

If you are planning a comprehensive repair or upgrade of the drivetrain area in your BMW and need other components from the same group, such as transmissions, mounting elements, or drivetrain-related parts, check out the available parts in the Other BMW category.

To compare the characteristics of sports drivetrains with solutions used in standard models, it is worth reading the analysis of differences in the construction of engines, brakes, and chassis in RS sports versions – details can be found in the article Audi RS vs other models – what is hidden under the hood and chassis?.