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BMW Differential and Gearing Upgrades

Upgrading various parts of the differential can have tremendous benefits in your car's performance. It's easy to forget that the differential is a source for making your car faster and handle better so it's often overlooked. The engine is not the only place to make the car faster. Our differential options vary from gearing upgrades to limited slip conversions. You can purchase the ring & pinion gear sets on their own (professional installation required) or have us build a diff around your own specifcations. The options are almost endless! Every custom-built diff is fully rebuilt with seals and bearings. We also design and supply bushing options to reduce driveline wind-up, finned differential covers for better cooling, and more!

Ratio Changes - Changing the differential gearing is one of the best and most-effective upgrades you can make on any BMW (old or new). By using a shorter (numerically higher) final drive ratio you are increasing your RPM relative to road speed - this puts you in a more powerful RPM range than before! Since you're in a 'meatier' part of the power band you're now putting down more power/torque to the ground. If you can trade outright top speed for faster acceleration at daily speeds then this is the perfect upgrade for you.

Limited Slip Upgrades - Sadly, many BMWs today are not equipped with a limited slip (posi-traction) differential. BMW has tried to compensate by using traction control that cuts power at the engine or applies the brakes to retard wheel spin (or a combination of both). But nothing beats the function and feel of a a true LSD which may be why BMW continues to use them in M cars. Our LSD upgrades can be done a number of different ways - a factory-type limited slip unit with either 2 or 3 clutch packs, helical type, OS Giken unit, or something truly custom. We can also vary ramp angles and setup to change the limited-slip behavior under acceleration, deceleration, and cornering. Need a custom diff? Call or e-mail to have a quote.

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Active Autowerke - Corporate Logo
T#:397248
Part#: 13-004
Ships in 9 Business Days
5% off MSRP $ 429.00

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 408.00 USD
Free Shipping
5% off MSRP
$ 429.00

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 408.00 USD
Free Shipping

The main mounting bolt for the differential in the E36 is susceptible to shearing off during extreme driving conditions. This can cause internal damage to your diff, leaving you stranded at the track or on the side of the road. Active Autowerke's differential support bracket eliminates this issue forever in under an hour installation.

 

Previously used Active Autowerke Part Number AA-DSB-E36

This product fits the following BMWs:
1992-1999 E36 323i 325i 328i M3

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Vargas Turbo Technologies - Corporate Logo
T#:51778109
Part#: VTT-X3-REAR-INSE
Ships on Aug 28, 2026
New Item
$ 109.99 USD
Free Shipping
$ 109.99 USD
Free Shipping
The VTT G0X Rear Bushing Insert Kit is a critical preventative upgrade for owners of BMW G-Series vehicles.
Rogue Engineering - Corporate Logo
T#:54388516
Part#: RE.484.FIX
Ships in 9 Business Days
New Item
$ 64.00 USD
Free Shipping on orders $49 and up
A common failure point on the BMW E46 M3 platform occurs when the side differential mounting bolt backs out, leading to stripped threads in the differential cover.

Vargas Turbo Technologies - Corporate Logo
T#:52129733
Part#: G8XDIFFINSFRT
Ships on Aug 28, 2026
New Item
$ 132.99 USD
Free Shipping
$ 132.99 USD
Free Shipping
The Vargas Turbo Technologies Front Diff Reinforcement Kit is a vital upgrade for high-horsepower S58-powered vehicles.

Vargas Turbo Technologies - Corporate Logo
T#:52129737
Part#: G8XDIFFINSTRO
Ships on Aug 28, 2026
New Item
$ 132.99 USD
Free Shipping
$ 132.99 USD
Free Shipping
The G8X Rear Billet Diff Insert Kit is a precision-machined reinforcement component that installs directly into the rear differential bushing.
Vargas Turbo Technologies - Corporate Logo
T#:52129738
Part#: VTT-G8X-LOCKDOWN
Ships on Aug 28, 2026
New Item
$ 739.99 USD
Free Shipping
$ 739.99 USD
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This black-anodized kit provides the reinforcement BMW intended but never fully realized in the factory design.

Enthusiast Bundles - Corporate Logo
T#:37419758
Part#: 049424LAEBKT
Ships in 1-2 days
Sale - Save 17% $ 1,381.99

This product was last offered at the strikethrough price on
05-05-2026

$ 1,149.99 USD
Free Shipping on orders $49 and up
Sale - Save 17%
$ 1,381.99

This product was last offered at the strikethrough price on
05-05-2026

$ 1,149.99 USD
Free Shipping on orders $49 and up

E36 188mm Reinforced Billet Aluminum Differential Cover

Engineered from high-quality 6061 billet aluminum, this differential cover is built for resilience and designed for performance. Hard-coat anodized for a sleek finish and superior corrosion resistance, it not only looks great but also brings functional improvements in strength and cooling. Turner Motorsport has added reinforced mounting ears to withstand the toughest driving conditions—preventing the breakages common with OEM covers.

This cover doesn’t just endure—it performs. The cover features strategically placed external fins on the rear face, base, and mounting ears to efficiently dissipate heat, keeping temperatures stable for optimal fluid longevity and differential health. Inside, the design promotes consistent oiling of the ring gear, reducing wear by ensuring critical cooling and lubrication. An integrated baffle keeps pressure stable and minimizes cavitation.

Compatibility is at the core of the design: it’s compatible with OEM gaskets or RTV, and it retains the factory bushing geometry for easy integration with rubber, poly, and even solid mounts. The upgraded -6AN drain and fill plugs allow expansion for an external oil cooler, ideal for high-performance applications. Plus, a 1/8 NPT port allows for real-time monitoring of differential fluid temperatures.

Key Benefits:

Reinforced mounting ears for robust support—no more broken ears during aggressive driving or track days Optimized cooling with fins on rear face, base, and mounting ears Removable air duct to direct airflow across fins for maximum temperature control Improved internal design to maintain consistent lubrication on the ring gear -6AN ports for external cooler compatibility, increasing fluid capacity and extending change intervals 1/8 NPT port for temperature sensor integration to monitor fluid heat Design Highlights:

Precision-milled from 6061 billet aluminum with a T6 hard-coat anodized finish Fits E36 medium case 188mm differentials Compatible with differential coolers (-6AN) and temperature sensors (1/8 NPT) Works with OEM speed sensor, OEM gasket, and oversized sway bars Designed for easy maintenance with a removable air duct and accessible drain/fill plug ECS Tuning E36 Polyurethane Transmission Mount Set – Street

The ECS Polyurethane Transmission Mounts in this kit provide a solid connection between transmission and chassis, enhancing stability and reducing unwanted drivetrain movement. Built for durability, these mounts feature polyurethane with a 70A durometer for a perfect balance of comfort and performance. Compared to OEM rubber mounts, polyurethane provides less deflection, better power transfer, and much longer life under stress.

Polyurethane’s natural resistance to water, oil, and wear ensures these mounts maintain shape and performance even under heavy compression, making them ideal for spirited driving and track use. The mounts include a mechanical interlock for secure, reliable performance—even under high-torque, forced-induction scenarios. For those seeking a more aggressive setup, ECS also offers an 80A durometer Race mount.

Key Features:

Reduces transmission movement, minimizing mis-shifts and over-revs High-quality polyurethane bonded to 304 Stainless Steel Engaging driving experience with enhanced feedback and control Available in Street (70A) and Race (80A) applications for tailored performance Enjoy smoother shifts, firmer power delivery, and a more engaging drive with the ECS Polyurethane Transmission Mounts.

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