BMW Differential and Gearing Upgrades

Harness unused potential. Drive with confidence. Engineered to maximize strength and cooling performance while utilizing the unused secondary factory differential mount for enhanced support and driveline stability.

Our Turner Motorsport Dual-Mount Differential Cover is purpose-built to reinforce one of the most critical components in the G8X M3/M4 drivetrain. From the factory, BMW includes a secondary bushing location in the rear subframe but leaves it unused. Our solution fully capitalizes on this overlooked feature, giving the differential a second point of support for improved rigidity, reduced movement, and enhanced driveline response under load.

This cover is more than just a mounting upgrade. It’s precision-machined from 6061-T6 billet aluminum for exceptional strength without unnecessary weight. An aggressive fin profile improves thermal efficiency, helping to lower fluid temperatures in high-stress environments. Inside, the cover features an embossed channel that mirrors the ring gear path, ensuring fluid stays in contact where it's needed most, improving cooling and lubrication in all conditions.

Whether you're carving corners on the street or pushing the limits on track, this differential cover is designed to keep your rear end cool, stable, and responsive.

Key Features and Benefits:

The dual-mount design utilizes the factory-provided secondary bushing location, adding critical support to reduce differential deflection, extend bushing life, and minimize wheel hop.
CNC-machined from 6061-T6 billet aluminum, offering high strength and a precise fit.
Built-in cooling fins increase surface area for improved heat dissipation and lower differential fluid temperatures.
Internally contoured to follow the ring gear profile, promoting consistent fluid coverage and effective lubrication.
Maintains a 1.1-liter fluid capacity, closely matching OEM specifications for ease of servicing.
Integrated -6 AN ports support the addition of an external differential cooler for increased fluid volume and extended service intervals.
Compatible with the factory differential fluid temperature sensor and includes provisions for 1/4” NPT aftermarket sensors.
Product Development:

Like all Turner Motorsport performance solutions, this differential cover was developed in-house by our dedicated Research and Development team. Designed, engineered, tested, and quality-inspected using advanced tools including FARO laser scanning for reverse engineering, SolidWorks 3D CAD modeling, in-house rapid prototyping, and extensive long-term testing, you can trust that this part meets the highest standards of fit, function, and durability.

From spirited street driving to full-throttle track days, the Turner Motorsport Dual-Mount Differential Cover ensures your G8X delivers the response, strength, and cooling capacity it needs when it matters most.

Sway bars transmit cornering forces from the outside wheels to the inside wheels, helping to keep the vehicle flat during cornering. This, in turn, reduces body roll and improves the driver's cornering confidence. OEM rubber sway bar bushings are designed with comfort in mind, allowing the sway bar to articulate while permitting additional movement, leading to less-than-ideal bar retention and causes unnecessary body roll.

Powerflex polyurethane sway bar bushings are firmer than factory rubber bushings, reducing body roll and keeping sway bars in check. Polyurethane bushings won't slop around like OEM bushings, allowing sway bars to function at their fullest potential.

Poweflex is a leading manufacturer of aftermarket suspension bushings. Using state of the art design and manufacturing, all replacement bushings are engineered to out-perform and out-last the ones that came in the car. Each line of bushings is meticulously tested and then re-tested to ensure perfect fitment and enduring quality through the life of the vehicle. A full lifetime warranty backs every one of their products and demonstrates the level of confidence and commitment Powerflex has to their customers. 

This part fits the following BMWs:
 

Servicing your rear differential at regular intervals is important to ensure you maintain both performance and a long lifespan. Over time, the differential fluid can break down, lose its lubricating properties, and become contaminated with metal shavings and debris. Regularly replacing the fluid ensures that the gears and limited slip differential clutch packs are adequately lubricated, reducing wear and tear. Regular maintenance also helps identify potential issues before they become major problems.

This kit includes Genuine BMW differential fluid designed specifically for your M Sport differential and a brand new fill plug. The factory plugs include a rubberized seal that compresses over time and may not seal properly when reused.

One unique aspect of performing this service is the removal of the lower differential temperature sensor. Unlike many typical BMW differentials, this differential does not use a traditional drain plug and instead uses the temperature sensor as a drain plug. This sensor is removed to drain the differential fluid and is replaced before refilling. If you'd like to replace this sensor as well (not included in this kit), please see our recommended items or search BMW part number 33107847469.

NOTE: This kit includes 3 500ml bottles of diff fluid. BMW claims that only 1 Liter of fluid is necessary, but we found that 2 500ml bottles were insufficient. The third bottle included also allows for a minor flush of the old differential fluid before refilling.

Bushings tends to wear over time and split or even break free from the internal sleeve, causing excessive movement and sloppy control feel. Genuine BMW bushings are the perfect option to restore suspension back to day 1 quality.

As a leading source of high performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts.  All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!

Genuine BMW Rubber Mounting Front -
This item fits the following BMW Chassis:
E82,E90,E92,E93

Gain a significant competitive edge with the MFactory Helical Limited Slip Differential, available at Turner Motorsport. This Helical LSD delivers a smooth and consistent distribution of power to your BMW's wheels, optimizing traction on the street, strip, or track. It's an essential addition for any BMW enthusiast.

Curious about the LSD's role? Without it, your car effectively becomes a one-wheel-drive vehicle, supplying torque to the wheel with less grip. The Helical LSD changes the game by allowing both wheels to receive power while limiting the speed difference between them, in contrast to open differentials commonly found in most vehicles.

Key Features:

• 30-Day Feel the Torque™ Money Back Guarantee: An industry-first assurance that lets you experience the difference. Plus, it's backed by a Limited-Lifetime Warranty for your peace of mind.
• Forged and Cryo-Tempered: Engineered for extreme durability and longevity, ensuring it can withstand the rigors of competition-level drag racing.
• Advanced Shot Peening Technology: Enhances surface hardness, making it well-equipped to handle the shocks of competition-level drag racing.
• Maintenance-Free Gears: Bid farewell to special fluids or rebuilds associated with typical plate LSDs. It's designed for hassle-free ownership.
• Lock-Free Operation: Ensures there's no adverse impact on steering response.

Break-In Procedure: For optimal performance, it's recommended to change the fluid after the first 3-400 miles of use.

Please note that any defects or warranty claims should be directed to Team MFactory.

Your rear differential is indirectly connected to your right foot through the engine and driveline, and connected to the seat of your pants through the chassis. Soft factory rubber differential bushings absorb vibrations between chassis and differential, providing comfort and softness in both of these connections.

Enter ECS Tuning's In-House Engineered Performance Polyurethane Differential Bushings. By eliminating the deflection factory rubber bushings permit, the connection between your right foot (and your seat) to the wheels is improved. Removal of this slop allows for crisper power transfer from differential to wheels, which means better throttle control while carving a canyon road, drag racing, sliding the rear end out, or just driving to work. This is achieved without the harshness or vibration associated with delrin or solid differential mounts.

Featuring a tough 88A durometer polyurethane and Black anodized 6061-T6 aluminum Sleeve, our Performance Polyurethane Differential Bushings are more resistant to chemicals, ozone degradation, road salt, and general wear and tear than factory rubber bushings, resulting in a longer service life.