BMW Differential and Gearing Upgrades for BMW 3 Series E46 (1999-2005)

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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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Turner Motorsport - Corporate Logo
T#:593924
Part#: 027030TMS01
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When both extreme-duty protection and saving every gram matters: the Turner Magnetic Differential Drain Plug.
Turner Motorsport - Corporate Logo
T#:337
Part#: TDR4680035
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Made in the USA For our Grand-Am Cup E46 M3s we wanted a fully solid differential mount setup. The advantages of a fully-solid aluminum set is that they last forever, quickens response in the suspension, and frees up horsepower to the wheels. These fully solid aluminum diff mounts are CNC machined and lightened for a direct replacement of the original rubber pieces.

By substituting aluminum for rubber we can take out all of the deflection and 'wind up' inherent to the original rubber pieces. The high deflection rate of the stock rubber means the suspension reacts slower as the bushing is compressed. The power used to compress that bushing is instead passed straight to the axles and wheels. And since there is no time lost to deflection, response is greatly improved. These diff mounts are only recommended for racecars since the aluminum transfers more noise and vibration.

This is a 3-piece set with a single front bushing and two rear bushings to press into the cover. They mount with the stock BMW hardware.

This item fits the following BMWs:
2001-2006 E46 BMW M3
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Turner Motorsport - Corporate Logo
T#:555025
Part#: TDR4680035-01
Ships in 10 Business Days
Sale - Save 28% $ 597.46

This product was last offered at the strikethrough price on
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$ 432.64 USD
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For our Grand-Am Cup E46 M3s we wanted a fully solid differential mount setup. The advantages of a fully-solid aluminum set is that they last forever, quickens response in the suspension, and frees up horsepower to the wheels. These fully solid aluminum diff mounts are CNC machined and lightened for a direct replacement of the original rubber pieces.

By substituting aluminum for rubber we can take out all of the deflection and 'wind up' inherent to the original rubber pieces. The high deflection rate of the stock rubber means the suspension reacts slower as the bushing is compressed. The power used to compress that bushing is instead passed straight to the axles and wheels. And since there is no time lost to deflection, response is greatly improved. These diff mounts are only recommended for racecars since the aluminum transfers more noise and vibration.

This is a 3-piece set with a single front bushing to be pressed in and two rear bushings pre-pressed into the cover. They mount with the stock BMW hardware.

This item fits the following BMWs:
2001-2006  E46 BMW  M3
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Powerflex - Corporate Logo
T#:362735
Part#: PFR5-4621
In Stock
$ 42.99 USD
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Differential bushings are responsible for keeping the differential in solid alignment while dampening drivetrain vibration. While OE rubber bushings are fine when they are new from the factory, aged and worn out rubber bushings create a multitude of issues that can range from annoying to dangerous. As a factory bushing ages, it begins to harden and become brittle. When this happens the bushing will actually shrink and allow for movement at the differential mounting point. At this point, the differential is free to shift under load causing a noticeable clunking noise under acceleration and deceleration and massively increasing the stress on the driveshaft and axles. Manual transmissions suffer the worst from this as it can make shifting difficult since the differential will shift when the clutch is engaged and disengaged.

By replacing these bushings with full polyurethane, the movement is eliminated since the mounting point is supported by a much stiffer material that will not harden or shrink over time. This means less stress on the driveshaft and axles and greater longevity of supporting components. 

Powerflex Black Series bushings are the ultimate in track and race bushings. Featuring 95A durometer polyurethane, Black Series bushings are 25% stiffer than street bushings. Engineered to perform, Powerflex performance polyurethane control arm bushings offer a supreme level of control, while still providing enough comfort for the street, with advanced polyurethane that reduces NVH that often accompanies lesser bushings. Expect improved acceleration response, more direct shifting feel and overall improved drivetrain composure with Powerflex performance polyurethane bushings.

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. 

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Powerflex - Corporate Logo
T#:33913480
Part#: PFR5-4621H
In Stock
$ 42.99 USD
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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#:34080712
Part#: PFR5-4620H
In Stock
$ 147.99 USD
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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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Packaged by Turner - Corporate Logo
T#:339943
Part#: E46-MY-DIFF
In Stock
$ 88.99

This product was last offered at the strikethrough price on
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Starting at $ 56.99 USD
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Starting at $ 56.99 USD
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These rubber bushings from Meyle are a direct replacement for the stock differential bushings in the E46 3-series, E83 X3 SAV, and Z4 Roadster. If your original bushings are worn (likely around 100,000 miles) these are a great replacement upgrade. The front bushings are the stock OEM type rubber bushings. The rear bushing is a Meyle HD upgrade over stock - about 15% stiffer than the originals. This means the bushing will not flex and twist as much. This puts more power to the wheels since power is no longer used up for 'torquing' the bushing. These are not race bushings; the rubber material is perfectly suitable for street use.

The non-M E46/E83/Z4 models use three differential mounts - two front bushings in the subframe and one rear mount in the diff cover. This set of bushings covers all three. You can opt to include new mounting hardware in the Options list below.

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi
2004-2010 E83 BMW X3 2.5i X3 3.0i X3 3.0si
2003-2008 Z4 BMW Z4 2.5i Z4 3.0i Z4 3.0si Roadster
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Powerflex - Corporate Logo
T#:378993
Part#: PFR5-4625X2
Ships in 8 Business Days
$ 94.99 USD
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$ 94.99 USD
Free Shipping

Differential bushings are responsible for keeping the differential in solid alignment while dampening drivetrain vibration. While OE rubber bushings are fine when they are new from the factory, aged and worn out rubber bushings create a multitude of issues that can range from annoying to dangerous. As a factory bushing ages, it begins to harden and become brittle. When this happens the bushing will actually shrink and allow for movement at the differential mounting point. At this point, the differential is free to shift under load causing a noticeable clunking noise under acceleration and deceleration and massively increasing the stress on the driveshaft and axles. Manual transmissions suffer the worst from this as it can make shifting difficult since the differential will shift when the clutch is engaged and disengaged.

By replacing these bushings with full polyurethane, the movement is eliminated since the mounting point is supported by a much stiffer material that will not harden or shrink over time. This means less stress on the driveshaft and axles and greater longevity of supporting components. 

Powerflex street bushings are ideal for street driven vehicles and those that see occasional autocross or track time. Need bushings for a dedicated track car? Powerflex Black Series bushings are the ultimate in track and race bushings. Featuring 95A durometer polyurethane, Black Series bushings are 25% stiffer than street bushings. Engineered to perform, Powerflex performance polyurethane control arm bushings offer a supreme level of control, while still providing enough comfort for the street, with advanced polyurethane that reduces NVH that often accompanies lesser bushings. Expect improved steering feel, turn in, more responsive handling and overall improved chassis composure with Powerflex performance polyurethane control arm bushings.

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. 

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Premium Differential Service Kit - E46 M3, E9X M3, E82 1 M Coupe ...
Includes BMW SAF-XJ limited slip differential fluid with FM booster
Packaged by Turner - Corporate Logo
T#:598688
Part#: E46M3DIFSERTMSKT
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This product was last offered at the strikethrough price on
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$ 277.83 USD
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Servicing your differential is an important job and should only be completed using high quality components! To ensure our customers are getting exactly what they need, we have put together this limited-slip differential service kit that includes all new fluid from BMW, a new BMW drain plug, and one of our new Titanium Magnetic Differential Drain Plugs!
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Packaged by Turner - Corporate Logo
T#:42133544
Part#: 835225790TKT
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This product was last offered at the strikethrough price on
08-04-2026

$ 59.72 USD
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This product was last offered at the strikethrough price on
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The kit includes 2 Quarts of Red line 75w90 - 57904 and brand new Rein rear diff oil drain plug M22x1.5
Packaged by Turner - Corporate Logo
T#:15710761
Part#: 33117525064-KT
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Often overlooked, scheduled rear differential service is very important. Over time gear lube breaks down causing bearings and internal components fail. Regular maintenance will keep your vehicle running properly for years to come. Kit includes 3 Bottles of Castrol SAF-XJ 75w140 2 Drain plugs
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OS Giken - Corporate Logo
T#:1387
Part#: BM237-HA
Ships in 2 Business Days
$ 1,950.00 USD
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$ 1,950.00 USD
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The M Dynamic limited slip unit on the M3 is designed to be a pure street car differential. It's simply not up to the rigors of professional or amateur racing. The OS Giken Super Lock LSD is giant step up in from a stock M3 lsd unit. It's ready for the extreme conditions of racing, offers 100% progressive locking capability, and is able to do this while operating smoothly and quietly. It's use of advanced technologies that make it perfect for both street cars AND pro race cars... and everything in between. We're excited to be carrying the OS Giken LSD unit in our performance catalog, as we've been using them in our own Championship winning M3 race cars.

OS Giken incorporated revolutionary new ideas when developing the their own limited slip diff, utilizing their accumulated racing knowledge and experience and over 4 years of development. Their design uses an unprecedented number of friction plates (up to 28 total!) for better locking force, better engagement/disengagement, and less generated heat. The end result of their efforts is the OS Giken's OS Super Lock LSD which offers incredible durability and reliability on street and track driven BMWs. The use of highest quality materials, precise machining, forged gears and sound engineering makes this LSD durable and reliable enough for road racing performance (which we can personally vouch for!). This is such a great design, in that it can be used in any situation -- whether it's for a street car, or a 100% Professional race car. Zero break-in required. Super smooth and quiet engagement, and 100% progressive locking capability. Professional installation is recommended.

This Limited Slip Differential Unit fits the following BMWs:
2001-2006 E46 M3 coupe & convertible
2008-2013 E9X M3 coupe & convertible
1991-1995 E34 M5 sedan
1999-2003 E39 M5 sedan
2006-2008 E85 Z4M Z4 M Coupe, Z4 M Roadster
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OS Giken - Corporate Logo
T#:34382136
Part#: BM237HAKT
Ships in 2 Business Days
$ 2,100.00 USD
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Upgrade to a better performing LSD, includes tune.
Packaged by Turner - Corporate Logo
T#:401688
Part#: 33117512980KT
Ships in 1 day
$ 367.99 USD
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$ 367.99 USD
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The perfect upgrade for any E46, this finned differential cover increases cooling to the rear differential to prevent over heating and possible damage. This is a complete kit including fluid and drain plugs.

Includes the following

  • Aluminum finned differential cover
  • Drain & fill plug with sealing o-ring
  • 2 Quarts of Redline 75w90
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Packaged by Turner - Corporate Logo
T#:556968
Part#: 33112282482KT3
Ships in 10 Business Days
Sale - Save 7% $ 676.14

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$ 627.61 USD
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$ 627.61 USD
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This kit includes Turner Motorsport solid aluminum differential race mounts pre installed in the differential cover for a quick install. These mounts where developed by Turner Motorsport for their Grand-Am Cup E46 M3 race cars, the advantages of solid aluminum mounts is increased suspension & drivetrain response, less drivetrain loss resulting in more wheel horsepower, and longevity - they effectively last forever. These CNC-machined mounts are a direct replacement for the stock rubber pieces, and have been lightened to remove excess weight. 

 

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Packaged by Turner - Corporate Logo
T#:15744025
Part#: 331175250640-KT
In Stock
Sale - Save 8% $ 274.99

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$ 252.18 USD
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Sale - Save 8%
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Often overlooked, scheduled rear differential service is very important. Over time gear lube breaks down causing bearings and internal components fail. Regular maintenance will keep your vehicle running properly for years to come. Three bottle of Genuine BMW Limited Slip Gear Lube 1 New Genuine BMW Drain/Fill plugs 1 ECS Magnetic Differential Oil Drain Plug Drain plug O-ring
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OS Giken - Corporate Logo
T#:34382134
Part#: LSD-TUNE
Ships in 2 Business Days
$ 150.00 USD
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$ 150.00 USD
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Packaged by Turner - Corporate Logo
T#:56616376
Part#: 27111226467KT2
Ships in 4 Business Days
New Item
$ 48.99 USD
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This Transfer Case Service Kit replaces degraded fluid and sealing hardware to maintain proper lubrication within the all wheel drive transfer case. Unserviced transfer case fluid breaks down into sludge and deposits, causing lubrication loss and internal component wear; this service kit prevents internal wear by renewing fluid properties and drain hardware.
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Packaged by Turner - Corporate Logo
T#:55965861
Part#: 30309175WKWVTKT2
Ships in 10 Business Days
New Item
$ 1,269.99 USD
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This AutoTech LSD Upgrade Kit pairs AutoTech’s highly engineered 188mm limited-slip differential carrier with a pair of Corteco output shaft seals, giving you everything you need for a leak-free install.
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Packaged by Turner - Corporate Logo
T#:41289766
Part#: 31521428678TKT
Back Ordered
$ 52.99

This product was last offered at the strikethrough price on
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$ 50.99 USD
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$ 50.99 USD
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This kit comes with the seal and both dust covers needed to re-seal your vehicles input shaft on the front differential.