BMW F20 F21 M135i N55 Rear Axle Differential Diff 3,08 Ratio 8659987 WARRANTY

Listing details

The differential is sold with a 90-day warranty! It was tested before removal and is in full working order.

BMW F20 F21 M135i N55 Rear Axle Differential Diff 3,08 Ratio is an original drivetrain component from the Differentials category, designed for rear axle installation. It ensures stable torque transfer and the correct gear ratio, which translates into predictable vehicle handling and consistent performance in both daily and dynamic driving. This is the ideal solution for users who expect factory-spec construction and wish to maintain the handling characteristics typical of the M135i version with the N55 engine.

Specifications and technical data

• SKU: 8659987
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 8659987
• Substitutable numbers: 8659987, 33108659987, 7555610, 33107555610, 2353286, 33102353286
• Location on the vehicle: Rear
• Category: Differentials

Purpose and function in the drivetrain

The presented rear differential is a component of the drivetrain in BMW F20/F21 series models in the M135i version with the N55 unit. It is responsible for distributing torque to the rear wheels and maintaining the correct gear ratio, which has a direct impact on acceleration, flexibility, and the overall refinement of the drivetrain. The applied 3.08 ratio allows for maintaining the factory operating characteristics of the system without interfering with the control electronics or engine software.

Benefits of using an original differential

Using an original differential in a BMW M135i ensures:

• Consistent handling – maintaining predictable traction and stability during acceleration and cornering.
• Proper fitment for the stock drivetrain – no need for modifications to mounts or the housing.
• Compatibility with factory traction and stability control systems, which facilitates diagnostics and service.
• The ability to restore factory driving parameters after a failure or wear of the previous axle.

For users who want to keep their car in a configuration close to factory specifications, this differential is a practical and technically safe solution.

Installation characteristics and application

The differential is designed for installation on the rear axle, in accordance with the factory drivetrain of the BMW F20/F21 M135i. The axle construction is prepared to work with stock half-shafts and suspension components, which facilitates installation in a workshop environment. By maintaining the original geometry and mounting points, replacing a worn component with the presented differential allows for reduced service time and minimizes the risk of fitment issues.

Condition and selecting the right part

The offered differential is a dismantled, used part, which allows for an economical repair while maintaining the original construction. When selecting the right part for a specific BMW vehicle, it is worth paying attention to the compatibility of the engine version, body type, and gear ratio to maintain the proper drivetrain characteristics. In case of doubt, it is helpful to compare data from the vehicle documentation or consult with a mechanic specializing in the BMW brand.

Expanding knowledge and gear ratio selection

If you want to better understand how the axle ratio affects acceleration, engine RPM, and driving comfort, it is worth checking out expert materials. Practical tips on selecting a drive axle and differential for your driving style can be found in the article Dismantled drive axles and differentials – how to choose ratios for your driving style, where definitions, configuration examples, and the most frequently asked user questions are discussed.

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 additional axles, differentials, or related parts, check out the available parts in the BMW Differentials category.