BMW F20 F21 M135i N55 Petrol Automatic Gearbox 8614187 GA8HP45Z - XKI WARRANTY

Listing details

The gearboxes are sold with a 90-day warranty! They were tested before removal and are in full working order. BMW F20 F21 M135i N55 Petrol Automatic Gearbox GA8HP45Z is an original, used automatic transmission designed for BMW 1 Series models with the N55 petrol engine. The gearbox belongs to a modern family of eight-speed transmissions, ensuring smooth gear shifts and efficient torque transfer in high-performance vehicles. This is a solution for users who expect factory compatibility and the maintenance of the operating characteristics typical of the M135i version.

Specifications and technical data

• SKU: 8614187
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 8614187
• Substitutable numbers: 24008614187, 8614187, 24008601209, 8601209, 24008486657, 8486657
• Fuel type: Petrol
• Gearbox type: Automatic
• Category: Automatic Transmission

Purpose and technical characteristics

The presented gearbox from the Automatic transmissions family has been designed to work with the N55 petrol engine in BMW F20 and F21 M135i models. The eight-speed GA8HP45Z design allows for precise adjustment of gear ratios to the character of the powertrain, which translates into efficient acceleration, stable RPM maintenance, and comfortable driving across the full speed range. This type of automatic transmission is used in high-performance cars, which is why its design accounts for the loads typical of dynamic operation. The applied architecture allows for fast gear shifting, reduced jerking, and effective utilization of the petrol engine's potential, both in daily driving and in more sporty modes.

Benefits of using the GA8HP45Z gearbox in the BMW M135i

Choosing this transmission for the BMW F20/F21 M135i provides a number of practical operational benefits:

• maintenance of the factory operating characteristics of the drivetrain,
• smooth and predictable gear shifts across the full load range,
• proper matching to the torque of the N55 engine,
• ability to use comfort and dynamic modes in accordance with the vehicle configuration,
• consistency with factory vehicle control systems. Thanks to this, installing the GA8HP45Z gearbox allows for restoring the proper operation of the drivetrain in cars where the previous transmission has become worn or damaged. For the user, this means stable handling, predictable throttle response, and proper cooperation with the vehicle's electronics.

Condition, origin, and fitment

The offered gearbox is a used item, sourced from the dismantling of a BMW vehicle. Such components are frequently chosen by users who want to reduce repair costs while maintaining the original manufacturer's specifications. In the case of automatic transmissions, it is essential to match the specific engine version and model generation – therefore, before purchasing, it is recommended to verify compatibility with the vehicle's VIN and factory configuration. The GA8HP45Z transmission is structurally prepared to work with the automatic transmission control system in the BMW F20/F21 M135i, which facilitates installation and integration with the existing wiring. Proper selection of the gearbox helps avoid issues with electronic communication, controller errors, or incorrect operation of driving modes.

Practical application of a used automatic transmission

Replacing an automatic transmission in a car with performance similar to the M135i is often one of the key service operations. Using an original, used gearbox from the same design family allows you to:

• maintain drivetrain operating parameters close to factory settings,
• preserve compatibility with existing controller software,
• minimize the risk of adaptation and calibration issues,
• reduce costs compared to purchasing a new transmission. If you are considering installing a used gearbox in your car and want to better understand how to assess its condition and fitment for a specific model version, the article on our blog will be helpful: Is it worth investing in used car parts?

Expanding the BMW drivetrain – related components

If you are planning a comprehensive repair or upgrade of the drivetrain area in your BMW and need other elements from the same group, such as a torque converter, control elements, or additional transmission sub-assemblies, check the available parts in the BMW automatic transmissions category. Selecting components within one brand and the same design group allows for maintaining consistency in operating parameters and facilitates future servicing. Thanks to this, the entire drivetrain remains tuned according to the manufacturer's specifications, which is important for both durability and vehicle comfort.