BTKUSA Dual Differential Mount

OEM CROSS-BRACE COMPATIBILITY

The factory cross braces remain fully compatible with this differential mount. They were removed in our product photos only to provide a clearer view of the mount.

IMPORTANT FITMENT NOTICE

This differential mount does not fit vehicles equipped with the M Performance differential. Please check your VIN to confirm that your vehicle has the same differential shown in our installed photos before ordering.

INSTALLATION NOTICE

Please be aware that factory differential positioning can vary significantly between individual X3 M40i and X4 M40i vehicles. This means the differential may not sit in exactly the same position on every vehicle.

We have revised the product to help accommodate these factory differences, but some variation may still be present during installation. We have not encountered this issue with any of our other differential mounts. The variation does not appear to be related to the vehicle’s model year or differential bushings.

Please keep this in mind during installation, and contact us if you need any assistance.

Upgrade the rear drivetrain of your BMW G01 X3 M40i or G02 X4 M40i with the BuiltToKillUSA Differential Mount. Precision CNC machined in San Clemente, California, this direct bolt-on upgrade adds support to the factory differential mounting system, reduces unwanted differential movement, and delivers more consistent power transfer under load.

Under hard acceleration, launches, and spirited driving, the factory rear differential can rotate and shift within its mounts. This movement may contribute to drivetrain slop, wheel hop, inconsistent power delivery, and additional stress on the factory differential mounting points and hardware. The BuiltToKillUSA Differential Mount helps stabilize the rear differential by distributing drivetrain loads more evenly and limiting excessive movement.

The result is a more responsive and controlled drivetrain with improved traction consistency and greater stability during acceleration and shifting. Whether your X3 M40i or X4 M40i is stock, lightly modified, or built for significantly more power, this mount provides the additional drivetrain support the factory mounting system was not designed to offer.

Performance Without Excessive NVH

Reducing Noise, Vibration, and Harshness was a major priority during development. Instead of using a fully solid-mounted design, this BMW differential mount features a carefully selected 80A polyurethane bushing.

The polyurethane bushing provides additional differential support while retaining excellent street manners, making this upgrade suitable for both daily-driven and high-performance vehicles. Across the complete BuiltToKillUSA differential mount lineup, there have been zero reported NVH complaints.

100% Made in the USA

Every component is proudly sourced and manufactured in the United States. The billet aluminum assembly, polyurethane bushing, hardware, CNC machining, anodizing, and final assembly are all completed domestically for exceptional quality, consistency, and durability.

Features

• Designed specifically for the BMW G01 X3 M40i and G02 X4 M40i

• Reduces excessive rear differential movement under load

• Helps minimize drivetrain slop and wheel hop

• Improves drivetrain response and stability

• Promotes more consistent traction during launches and shifting

• Helps distribute load across the factory differential mounting system

• Performance-focused 80A polyurethane bushing

• Designed to avoid the excessive NVH associated with fully solid mounts

• Precision CNC-machined billet aluminum construction

• Durable anodized finish

• Direct bolt-on installation

• 100% sourced and manufactured in the USA

• All installation hardware included

Installation

Professional installation is recommended because installation requires a rivet nut, also known as a rivnut, tool. If you plan to complete the installation yourself, rivnut tools are inexpensive and widely available through Amazon and most local hardware stores.

All hardware required to install the differential mount is included. The rivnut installation tool is not included.

Proudly designed, CNC machined, anodized, assembled, and manufactured in San Clemente, California.