BTKUSA X3/X4 M40I Dual Diff Mount

THE OEM CROSS BRACES STILL FIT WITH THE DIFF MOUNT ITS REMOVED IN OUR PHOTOS FOR A CLEARER IMAGE OF THE MOUNT 

DOES NOT FIT M PERFORMANCE DIFF PLEASE CHECK YOUR VIN TO SEE IF YOU HAVE THE SAME DIFF AS SHOWN IN THE ON CAR PHOTOS

IMPORTANT FITMENT NOTICE: The X3/X4 M40i platform has significant factory variation in differential positioning, meaning each differential may sit slightly differently from vehicle to vehicle. Early production units experienced occasional fitment issues due to these variations. We have since revised the design to better accommodate these differences, with no reported installation issues on updated units.
However, factory positioning variations are still present and are not specific to any model year or bushing type. Please keep this in mind during installation and contact us if you experience any fitment difficulties.

 

ALL HARDWARE REQUIRED FOR INSTALLATION IS INCLUDED

PROUDLY MADE IN SAN CLEMENTE, CALIFORNIA 🇺🇸

 

The BuiltToKillUSA G01 X3 M40i / G02 X4 M40i Differential Mount is engineered to eliminate one of the biggest weak points in the drivetrain by adding additional support and reducing excessive differential movement during hard acceleration, launches, and spirited driving.

The factory rear differential mounting system allows the differential to rotate and shift under load. As power levels increase, this movement can lead to drivetrain slop, inconsistent power delivery, wheel hop, and additional stress on the factory differential mounting points and hardware. Our upgraded differential mount stabilizes the differential by distributing load more evenly while limiting unwanted movement—without introducing the harshness of a fully solid-mounted setup.

Precision CNC machined and engineered specifically for the G01 X3 M40i and G02 X4 M40i, this mount improves drivetrain response, traction consistency, and overall vehicle stability while helping reduce stress on the factory differential mounting system.

Every component of the BuiltToKillUSA Differential Mount is proudly 100% sourced and manufactured in the United States. From the billet aluminum components to the hardware, polyurethane bushing, machining, anodizing, and final assembly, every part is produced domestically to deliver the highest level of quality, consistency, and durability.

One of our primary goals during development was minimizing NVH (Noise, Vibration, and Harshness). Instead of using a fully solid-mounted design, we incorporated a specially selected 80A polyurethane bushing that effectively spreads drivetrain loads while maintaining excellent street manners. Across our entire lineup of differential mounts, we have received zero NVH complaints, making this an ideal upgrade for both daily driven and high-performance vehicles.

Features

• Designed specifically for G01 BMW X3 M40i & G02 BMW X4 M40i
• 100% USA sourced and manufactured components
• Reduces differential movement under load
• Helps reduce stress on the factory differential mounting system
• Improves throttle response and drivetrain stability
• Increases traction consistency during launches and shifting
• Performance-focused polyurethane bushing design without the excessive NVH common with fully solid-mounted competitors
• Precision CNC-machined billet aluminum construction
• Long-lasting anodized finish
• Direct bolt-on installation
• 80A Polyurethane Bushing Design

Whether your X3 M40i or X4 M40i is stock, lightly modified, or built for significantly increased power, the BuiltToKillUSA Differential Mount provides the drivetrain support and confidence the factory mounting system simply wasn’t designed to offer.

PROFESSIONAL INSTALLATION IS RECOMMENDED, as installation requires a rivet nut (rivnut) tool. This inexpensive tool can be purchased through Amazon or most local hardware stores if you plan to complete the installation yourself.

EVERY COMPONENT FROM THE POLYURETHANE BUSHING AND HARDWARE TO THE COMPLETE CNC-MACHINED BILLET ASSEMBLY IS PROUDLY DESIGNED, MACHINED, AND MANUFACTURED IN THE USA.