BMW Differential and Gearing Upgrades for BMW Z Series E85/6 (2003-2008)

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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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Rein - Corporate Logo
T#:38890943
Part#: HWU0065
In Stock
$ 23.99 USD
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$ 23.99 USD
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As components in the differential begin to wear, metal particles become loose in the diff fluid, which can lead to excess wear. This magnetic plug pulls these particles out of suspension, helping to reduce wear over time. Replaces BMW # 33117525064
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ECS - Corporate Logo
T#:366828
Part#: 009314ECS01A
In Stock
Sale - Save 25% $ 62.99

This product was last offered at the strikethrough price on
06-13-2026

$ 47.24 USD
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Sale - Save 25%
$ 62.99

This product was last offered at the strikethrough price on
06-13-2026

$ 47.24 USD
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You use a magnetic drain plug for your engine oil, right? Why not apply the same proactive thinking to the differential too? This is a direct replacement magnetic differential drain plug for your BMW. It will catch and retain fine and larger metal particles in your diff oil. If you're proactive in your diff oil servicing, you will catch a minor issue long before it becomes a headache. Diff drain plug includes one sealing o-ring. Direct replacement for Genuine BMW part number(s): 33117525064, 33110308370, 33110152626
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ECS - Corporate Logo
T#:583896
Part#: 000920ECS01
In Stock
Sale - Save 25% $ 42.99

This product was last offered at the strikethrough price on
06-14-2026

$ 32.24 USD
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Sale - Save 25%
$ 42.99

This product was last offered at the strikethrough price on
06-14-2026

$ 32.24 USD
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Ensure the longevity of your BMW's drivetrain with ECS Tuning's Magnetic Plugs. These plugs are meticulously engineered in-house to provide a perfect fit and feature a permanent magnet attached to the plug body. The magnet effectively attracts and captures tiny abrasive and ferrous metal particles, preventing their circulation through lubrication systems. Metal particles can accumulate due to various conditions such as normal wear, machining operations, casting flaws, and stress usage, leading to excessive wear of vital components. ECS Tuning's Magnetic Plugs help alleviate this concern by trapping these particles, thus safeguarding the internal components of your drivetrain. With a convenient 17mm hex head design, these plugs eliminate the need for special tools required for OEM plugs.

Key Benefits:

  • Removes abrasive metal particles from drivetrain fluid
  • Prevents excessive wear to internal components
  • Meticulously engineered for a perfect fit
  • Features a permanent magnet for efficient particle capture
  • Convenient 17mm hex head design for easy installation
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ECS - Corporate Logo
T#:363117
Part#: 002447ECS03
In Stock
Sale - Save 25% $ 88.99

This product was last offered at the strikethrough price on
06-13-2026

$ 66.74 USD
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Sale - Save 25%
$ 88.99

This product was last offered at the strikethrough price on
06-13-2026

$ 66.74 USD
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BMW E46 Z4 Rear Polyurethane Differential Bushing Performance is the ultimate upgrade for enhancing the connection between your BMW's chassis and differential. Designed by Turner Motorsport, this performance bushing replaces the soft factory rubber with durable polyurethane, offering superior control and response. By minimizing vibrations and reducing deflection, this bushing ensures a more direct and responsive driving experience, making it a must-have for any performance-oriented BMW E46 or Z4 owner.

  • Enhanced Performance: Replaces the soft factory rubber with durable polyurethane for improved driveline response.
  • Reduced Vibrations: Minimizes vibrations between the chassis and differential, providing a more connected driving experience.
  • Increased Durability: Made from high-quality polyurethane, offering long-lasting performance under demanding conditions.
  • Improved Control: Reduces deflection, ensuring a more precise and responsive handling experience.
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Packaged by Turner - Corporate Logo
T#:339943
Part#: E46-MY-DIFF
In Stock at Vendor
$ 78.99

This product was last offered at the strikethrough price on
05-07-2026

Starting at $ 74.99 USD
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Starting at $ 74.99 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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OEM BMW Rear Differential Mount - E46, E83 X3, E85 Z4
We Price Match - Give Us A Call or Chat!
Febi - Corporate Logo
T#:12525
Part#: 33176751808
In Stock
$ 38.99

This product was last offered at the strikethrough price on
06-23-2026

$ 27.99 USD
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$ 27.99 USD
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RUBBER MOUNTING REAR:331020

OS Giken - Corporate Logo
T#:34382136
Part#: BM237HAKT
Back Ordered
$ 2,100.00 USD
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Upgrade to a better performing LSD, includes tune.
Lemforder - Corporate Logo
T#:398994
Part#: 33173449082
Back Ordered
$ 27.99 USD
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Bushings tends to wear over time and split or even break free from the internal sleeve, causing excessive movement and sloppy control feel. OEM Lemförder bushings are the perfect option to restore suspension back to day 1 quality.

OEM Lemförder is an engineering company that focuses on high-quality, precision manufacturing of critical suspension and steering components. Providing exceptionally high quality parts directly to BMW, as well as 50+ other big name automotive companies, such as Mercedes and Audi, their history of reliability and variety of offered parts makes them one of the biggest names for a go-to OEM parts provider. Lemförder parts place an important emphasis on design, production, and assembly, ensuring maximum reliability. They even coat all parts possible with corrosion protection for extended longevity.

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!

This item fits the following BMW Chassis:
E83 X3,E85,E86,E89 Z4

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Differential Service Kit
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:15744025
Part#: 331175250640-KT
In Stock
Sale - Save 5% $ 274.99

This product was last offered at the strikethrough price on
05-03-2026

$ 260.36 USD
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Sale - Save 5%
$ 274.99

This product was last offered at the strikethrough price on
05-03-2026

$ 260.36 USD
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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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Lemforder - Corporate Logo
T#:15674
Part#: 33176770788
In Stock
$ 17.99

This product was last offered at the strikethrough price on
06-08-2026

$ 12.50 USD
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$ 12.50 USD
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RUBBER MOUNTING FRONT
OEM Febi Rear Differential Carrier Bushing - Rear Positiom - E82/88 E...
Rear Position
We Price Match - Give Us A Call or Chat!
Febi - Corporate Logo
T#:382585
Part#: 33176770866
In Stock
$ 47.99

This product was last offered at the strikethrough price on
09-04-2026

$ 34.99 USD
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$ 34.99 USD
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