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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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Powerflex - Corporate Logo
T#:37925919
Part#: PFR54030KT
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Lock your differential down with this complete kit featuring Powerflex's Dual-Mount bracket and street bushings
Powerflex - Corporate Logo
T#:33913480
Part#: PFR5-4621H
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The Powerflex Rear Diff Front Mount Bushing for the BMW E46 3 Series and Z4 is a premium upgrade designed to enhance the stability and performance of the drivetrain. Here’s an alternative description:

  • High-Performance Polyurethane: Powerflex bushings are made from advanced polyurethane, which is significantly more durable than standard rubber. This material resists wear, deformation, and the effects of heat, oil, and contaminants, making it a long-lasting solution for high-performance applications.

  • Purpose: The rear differential front mount is subjected to high levels of stress during acceleration and cornering. Over time, the stock rubber bushing can degrade, causing excessive movement in the differential. The Powerflex bushing eliminates this movement, allowing for improved drivetrain control and reducing unwanted flex.

  • Key Features:

    • Enhanced Rigidity: By replacing the softer OEM rubber with Powerflex’s stiffer polyurethane, this bushing minimizes differential movement under load, resulting in improved throttle response and sharper handling.
    • Improved Longevity: Unlike the factory rubber mounts, which can crack and wear out over time, the polyurethane construction ensures long-lasting performance and reliability.
    • Performance-Oriented Design: Powerflex’s bushing is engineered to handle the increased demands of spirited driving and track use, offering better control without sacrificing comfort.
  • Benefits:

    1. Improved Power Transfer: Reducing differential movement helps direct more power to the wheels, improving acceleration and delivering a more connected driving feel.
    2. Better Handling and Stability: With less flex in the differential, the car becomes more stable, particularly during cornering and high-speed driving, enhancing overall handling precision.
    3. Durable and Maintenance-Free: Polyurethane bushings are resistant to common automotive chemicals, heat, and road debris, providing a set-and-forget solution that lasts longer than rubber components.
  • Fitment: This bushing is designed as a direct replacement for the front mount of the rear differential in BMW E46 3 Series and Z4 models. It installs easily, without requiring modifications, and offers an immediate improvement in drivetrain response.

In summary, the Powerflex Rear Diff Front Mount Bushing is an essential upgrade for BMW E46 and Z4 drivers who want to improve drivetrain rigidity, reduce flex, and enhance overall performance. This bushing provides a durable, long-lasting solution that’s perfect for both street and track use, delivering better power transfer and handling.

4o


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Powerflex - Corporate Logo
T#:16907150
Part#: PFR5-4024
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BMW G8X Rear Diff Front Mounting Bushing (Street) is a high-performance upgrade designed to enhance the stability and control of the BMW G8X's rear differential. This bushing features a robust construction combining CNC-machined aluminum and high-quality polyurethane to provide superior drivetrain support and minimize deflection.

  • Improved Drivetrain Stability: Reduces drivetrain deflection for better handling and control.
  • Enhanced Launch Performance: Minimizes wheel-hop during aggressive starts and hard launches.
  • Durable Construction: Made from black anodized 2011-T6 aluminum and high-strength polyurethane.
  • Choice of Hardness: Available in signature purple 80A durometer or black 95A durometer polyurethane to suit different driving needs.
  • Direct Replacement: Designed as a full bushing replacement for easy installation and improved performance.
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Powerflex - Corporate Logo
T#:34080712
Part#: PFR5-4620H
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The Powerflex Heritage Rear Differential Mount for the BMW E46 M3, available through outlets like Turner Motorsport, is an ideal upgrade for enthusiasts seeking to enhance the performance and durability of their car's rear differential while preserving its classic appearance. The Heritage Series is tailored for those who prefer a more subtle aesthetic than the brightly colored bushings typical of Powerflex's standard line.

Key features:

  • Heritage Polyurethane Composition: The bushings are made from high-performance polyurethane, providing superior resistance to wear, cracking, and degradation compared to the original rubber mounts. This helps improve handling without compromising ride comfort.
  • Classic Appearance: Unlike the regular Powerflex bushings, which come in bright colors (yellow or purple), the Heritage Series bushings are finished in a muted dark green/black, allowing them to blend seamlessly into the undercarriage of the vehicle, ideal for those who prefer a more OEM look.
  • Enhanced Handling and Stability: The rear diff mount works to reduce the unwanted movement of the differential, which translates to improved traction, better throttle response, and more consistent handling in high-load scenarios like hard cornering or acceleration. This significantly reduces wheel hop and enhances rear-end stability.
  • Direct Fitment: These mounts are designed to be a direct replacement for the factory bushings, requiring no additional modifications. This makes them an excellent choice for both DIY and professional installs.
  • Perfect for Street and Track Use: Combining durability and flexibility, this mount is suitable for E46 M3s that see a mix of daily driving and occasional track use, offering the best of both worlds by improving responsiveness while maintaining comfort.

Turner Motorsport often emphasizes the balance of performance and OEM-like comfort with these mounts, making them an excellent choice for those wanting to upgrade their rear differential mounting without detracting from the car's original feel.

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Powerflex - Corporate Logo
T#:38229087
Part#: PFR5-631H
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This Rear Diff Front Mount Bushing is perfect for BMW E34 and E32 owners looking to improve their vehicle’s rear suspension dynamics and drivetrain stability. It’s an ideal choice for enthusiasts who want better control and responsiveness without sacrificing too much ride comfort, offering a long-lasting, low-maintenance upgrade for daily driving or performance use.
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Powerflex - Corporate Logo
T#:34549569
Part#: PFR5-725BLK
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The Powerflex Rear Differential Front Bushings for the BMW E60 5-Series and E63 6-Series are specifically engineered to optimize the performance of the rear differential assembly. By replacing the factory rubber bushings with robust polyurethane, these bushings provide numerous benefits that enhance vehicle handling and stability.

Key Benefits:

  1. Enhanced Power Delivery: The firmer polyurethane material reduces flex and movement in the differential mount, ensuring better alignment and stability. This improvement leads to more effective power transfer from the engine to the wheels, resulting in enhanced acceleration and performance.

  2. Increased Longevity: Powerflex bushings are designed to withstand harsh driving conditions, resisting wear from heat, oil, and road debris. Unlike conventional rubber bushings, which can deteriorate over time, these polyurethane bushings maintain their performance over a longer period.

  3. Improved Handling Dynamics: By minimizing unwanted movement in the rear differential, these bushings enhance the vehicle’s handling characteristics. Drivers will experience reduced body roll and increased traction, allowing for a more controlled and confident driving experience, especially in high-performance situations.

  4. Superior Road Feel: The stiffer construction of these bushings enhances feedback to the driver, improving steering response and overall road feel. This connection allows for a more engaging driving experience, as drivers can better sense the vehicle’s dynamics.

  5. Simple Installation: These bushings are specifically designed to fit the E60 and E63 models directly into the existing differential mounts. The installation process is straightforward, requiring no modifications, which makes it an accessible upgrade for DIY enthusiasts.

This upgrade is perfect for BMW E60 5-Series and E63 6-Series owners seeking to enhance their vehicle’s rear differential performance and overall handling capabilities. The Powerflex Rear Differential Front Bushings offer a reliable solution for improving the effectiveness of the rear suspension system, making them suitable for everyday driving as well as spirited performance applications.

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Powerflex - Corporate Logo
T#:16907151
Part#: PFR5-4024B
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Powerflex - Corporate Logo
T#:13793032
Part#: PFR5-631
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Differentials serve the key purpose of transmitting power from the driveshaft to the axles. Factory rubber bushings absorb some of this power to allow for cushy, comfortable acceleration, at the expense of performance. Many OEM differential bushings are fast-wearing and failure prone, resulting in driveline slop and thunks when shifting or going over bumps. Powerflex polyurethane differential bushings are firmer than OEM rubber bushings, eliminating associated driveline slop and allowing for the crisp application of power to the ground, resulting in better throttle response and control. Powerflex is the number one selling suspension bushing manufacturer in Europe. Their experience with polyurethane bushing material and state-of-the art manufacturing techniques allows them to produce premium performance bushings, made to exact-fit standards. Powerflex performance polyurethane bushings are built to last longer than OEM rubber bushings, while improving performance and allowing for a more engaging driving experience. Use of Powerflex Copper Grease PCG1 is recommended for ease of installation. Periodic reapplication is recommended to extend squeak-free service life of bushings. Powerflex Black Series bushings are the ultimate in track and race bushings. Need bushings for a car that's street-driven? Powerflex street bushings are an ideal alternative for street driven vehicles and those that see occasional autocross or track time. Powerflex is proud to offer a lifetime warranty to the original purchaser on all products.
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Powerflex - Corporate Logo
T#:33946923
Part#: PFR5-300H
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The Powerflex Rear Diff Bushing for BMW Z3, E30 3 Series, and 318Ti is a high-performance replacement for the factory rubber bushings in the rear differential. This upgrade is ideal for improving handling, power delivery, and drivetrain stability, especially on aging vehicles where the original bushings may have deteriorated.

Key Features:

  1. Polyurethane Construction: Unlike the OEM rubber bushings, Powerflex bushings are made from durable polyurethane, which resists wear from exposure to heat, oil, and road debris. This increases the longevity of the bushing and ensures consistent performance over time.

  2. Handling Improvements: The stiffer polyurethane material significantly reduces the flex and movement of the differential during acceleration, braking, and cornering. This helps improve the overall stability and precision of the vehicle’s rear-end, enhancing cornering performance and delivering better power transfer to the wheels.

  3. Versions for Different Needs:

    • Road Series: Designed for daily driving, these bushings offer an excellent balance of performance and comfort, maintaining near-factory levels of ride quality while improving rear differential control.
    • Black Series: These bushings are made from a much stiffer polyurethane (95A durometer) and are designed for motorsport or track applications. They provide maximum control and minimal flex, at the expense of an increase in NVH (noise, vibration, and harshness).
  4. Direct Fitment: These bushings are designed as direct replacements for the stock bushings, making installation relatively straightforward. This is especially useful for older models like the E30 and Z3, where original bushings may have degraded or cracked, causing clunking noises and excessive differential movement.

  5. Performance Gains: With reduced differential movement, drivers can expect sharper throttle response, improved traction under load, and better cornering dynamics, making it a perfect upgrade for those who want to refresh and enhance the performance of their BMW's rear suspension.

Application:

  • BMW Z3
  • BMW E30 3 Series
  • BMW E36 318Ti (Compact)

This Powerflex rear diff bushing upgrade is ideal for anyone looking to improve the handling characteristics of their BMW while adding durability and reliability to the drivetrain setup.

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Powerflex - Corporate Logo
T#:34549562
Part#: PFR5-526H
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The Powerflex Rear Differential Rear Mount Bushings for the BMW E39 5 Series are designed to provide a significant upgrade to the vehicle's rear differential system by replacing the stock rubber bushings with high-performance polyurethane. This enhancement leads to improved handling, stability, and durability.

Key Benefits:

  1. Enhanced Differential Control: The stiffer polyurethane material reduces unwanted movement and flex in the differential mount, ensuring better alignment and stability under load. This translates to improved power delivery and handling during cornering and acceleration.

  2. Increased Longevity: These bushings are crafted to resist wear and degradation from oil, heat, and road debris, offering superior durability compared to traditional rubber bushings. This longevity ensures that the performance benefits are maintained over time.

  3. Improved Driver Feedback: By minimizing movement in the rear differential, these bushings enhance the connection between the vehicle and the driver. This results in better feedback and control, allowing for a more engaging driving experience.

  4. Direct Fit for Easy Installation: Designed specifically for the E39 5 Series, these bushings fit directly into the existing differential mounts, facilitating a hassle-free installation process without the need for modifications.

This upgrade is perfect for BMW E39 5 Series enthusiasts who want to improve their vehicle's handling and performance, making it suitable for both daily driving and spirited performance applications. The Powerflex Rear Differential Rear Mount Bushings provide a reliable solution to enhance the overall effectiveness of the rear suspension system.

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Elring - Corporate Logo
T#:54852011
Part#: B16.900
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This high-grade Elring replacement gasket set is engineered for drivers who demand factory-level reliability and zero-compromise sealing performance.
Powerflex - Corporate Logo
T#:44835449
Part#: PFR54030BKT
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Lock your differential down with this complete kit featuring Powerflex's Dual-Mount bracket and race/track bushings


Powerflex - Corporate Logo
T#:54281644
Part#: PFR5-325H
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The Powerflex Heritage Series is a premium motorsport upgrade engineered to eliminate critical differential deflection. Molded from an advanced, proprietary polyurethane formula, this bushing stabilizes the differential nose under high-torque loading.
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Powerflex - Corporate Logo
T#:54281641
Part#: PFR5-326H
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The Powerflex Heritage Collection replaces the soft factory unit with an engineered, high-performance polyurethane compound. It is designed to constrain differential rotation and stabilize the driveline without changing the classic aesthetic of the vehicle undercarriage.
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Powerflex - Corporate Logo
T#:54352781
Part#: PFR5-1625H
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Powerflex - Corporate Logo
T#:54352762
Part#: PFR5-2025H
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By stabilizing the differential's position relative to the subframe, the rear diff bushing helps maintain static axle angles under extreme loads, reducing wear on peripheral drivetrain components and providing a highly predictable, repeatable platform for track setups.
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Powerflex - Corporate Logo
T#:54317182
Part#: PFR5-324H
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Ensure your build operates at peak mechanical efficiency. Eliminate driveline slop and secure your differential assembly with track-proven engineering.
Elring - Corporate Logo
T#:53008820
Part#: 33108860348
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The Axle Shaft Seal is a critical component designed to prevent fluid leaks around the axle shaft, ensuring the proper function of the vehicle’s drivetrain system. This seal helps maintain the integrity of the differential, preventing dirt, water, or contaminants from entering the diff while keeping lubricants contained.
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Elring - Corporate Logo
T#:44767282
Part#: 082.770
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Eliminate differential leaks with all new output shaft axle seals from Elring Replaces BMW p/n 33107568368, 33107505605, & 33100152629
Elring - Corporate Logo
T#:54852004
Part#: B46.610
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This OEM-quality replacement shaft seal from Elring is the perfect fix for keeping your gear oil where it belongs.

Elring - Corporate Logo
T#:44733256
Part#: 703.190
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If your differential is leaking fluid from the input shaft at the front of the diff case, there is a good chance this seal is faulty. Replace your leaking seal with this new seal from Elring to prevent further fluid loss and prevent damage to your differential. Replaces BMW p/n 33121213949, 33121212197, & 33121204847
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Powerflex - Corporate Logo
T#:54352763
Part#: PFR5-2025BLK
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The Powerflex Black Series is engineered for maximum performance and minimum deflection