BMW Differential and Gearing Upgrades for BMW E90 M3 S65 4.0L

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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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BMW Differential Seal - Rear Axle
For pre LCI models 335i, 335is and 335xi, from production date 07/2009
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Genuine BMW - Corporate Logo
T#:31655802
Part#: 33108860346
Ships in 2 Business Days
2% off MSRP $ 96.58

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

$ 94.99 USD
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2% off MSRP
$ 96.58

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

$ 94.99 USD
Free Shipping on orders $49 and up
Proper fluid levels in the rear differential are crucial for its performance and longevity. Ignoring a leaking shaft seal can lead to severe damage. Each vehicle requires two seals.
Differential Input Shaft Seal - Priced Each
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Corteco - Corporate Logo
T#:44021076
Part#: 33121213949
In Stock at Vendor
$ 27.99

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

$ 26.99 USD
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$ 26.99 USD
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Genuine BMW Differential Service Kit - E46 M3, E90 E92 E93 M3, Z4 M, ...
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Genuine BMW - Corporate Logo
T#:370652
Part#: E46M3DIFSER
In Stock
$ 226.99

This product was last offered at the strikethrough price on
06-03-2026

$ 212.99 USD
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$ 212.99 USD
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Premium Differential Service Kit - E46 M3, E9X M3, E82 1 M Coupe ...
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Includes BMW SAF-XJ limited slip differential fluid with FM booster
Packaged by Turner - Corporate Logo
T#:598688
Part#: E46M3DIFSERTMSKT
In Stock
Sale - Save 8% $ 301.99

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

$ 277.83 USD
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Sale - Save 8%
$ 301.99

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

$ 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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Genuine BMW Differential Carrier Bushing - Rear Position - E90 E92 E9...
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Genuine BMW - Corporate Logo
T#:60061
Part#: 33312283384
Ships in 2 Business Days
2% off MSRP $ 103.99

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

$ 101.99 USD
Free Shipping
2% off MSRP
$ 103.99

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

$ 101.99 USD
Free Shipping
This is the rear differential carrier bushing located in the rear subframe.
Victor Reinz Shaft Seal with Lock Ring - Differential Output Shaft (7...
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Victor Reinz - Corporate Logo
T#:596464
Part#: 33107510289
In Stock at Vendor
$ 22.99

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

$ 22.00 USD
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$ 22.00 USD
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Limited Slip Differential - S54 3.2L & S65 4.0L Engines
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Wavetrac - Corporate Logo
T#:363875
Part#: 30309165WKWVT
Back Ordered
$ 1,595.00 USD
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$ 1,595.00 USD
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Upgrade your BMW S54 3.2L & S65 4.0L Engines with the Turner Motorsport Wavetrac Limited Slip Differential. Featuring patented Wavetrac® design, this innovative differential automatically enhances grip in low traction conditions, providing superior performance compared to traditional designs. Crafted with high-strength 9310 steel gears and ARP® fasteners, this differential ensures durability and reliability. Maintenance-free and backed by a limited lifetime warranty, the Wavetrac® differential offers peace of mind and exceptional performance for your BMW.

  • Patented Wavetrac® design improves grip in low traction conditions
  • High-strength 9310 steel gears ensure durability
  • Maintenance-free operation for the lifetime of the differential
  • Backed by a limited lifetime warranty for added assurance
  • Enhances performance and driving experience for BMW owners
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Permatex "Right Stuff" Gasket Maker
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Permatex - Corporate Logo
T#:361188
Part#: 29208
In Stock
$ 33.19 USD
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Creates gaskets the same way as OEM car manufacturers

E46 M3, E9X M3, E34 M5, E39 M5, Z4 M OS Giken Super Lock Limited Slip...
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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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Differential And LSD Tune
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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.
Race Polyurethane Differential Bushing, Rear Position - E8X, E9X ...
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Powerflex Black Series - Corporate Logo
T#:376534
Part#: PFR5-1226B
Ships in 1 Business Day
$ 52.99 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. 

This part fits the following BMWs:
2008 - 2013 E82 1 Series Coupe 128i 135i 135is 1M Coupe
2006 - 2008 E90 323i 325i 325xi 328i 328xi 330i 330xi 335i 335xi
2009 - 2012 E90 323i 323i 328i 328xi 335d 335i 335i xDrive 335xi
2006 - 2009 E91 325xi 328i 328xi
2009 - 2011 E91 328i 328xi 
2007 - 2013 E92 328i 328xi 335i 335xi
2007 - 2013 E93 328i 335i

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Genuine BMW Axle Seal Driver - BMW E46 M3, E9X M3, E82 1M, E39 M5, E6...
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Genuine BMW - Corporate Logo
T#:172491
Part#: 83300495143
Ships in 2 Business Days
$ 82.99 USD
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$ 82.99 USD
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This Axle Seal Driver is used to install 76x50x10 axle seals on TYP210 and TYP215 differentials, ensuring the seals are fully seated.