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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 Titanium Magnetic Differential Drain Plug - M22x1.5

T#:593924

Part#: 027030TMS01

In Stock

Sale - Save 25% $ 89.99

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

$ 67.49 USD

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$ 89.99

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$ 67.49 USD

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When both extreme-duty protection and saving every gram matters: the Turner Magnetic Differential Drain Plug.

Rear Differential Mounts - Turner Solid Aluminum - E46 M3

T#:337

Part#: TDR4680035

Ships in 7 Business Days

Sale - Save 25% $ 232.99

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

$ 174.74 USD

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$ 232.99

This product was last offered at the strikethrough price on
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$ 174.74 USD

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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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E46 M3 Turner Motorsport Solid Aluminum Differential Race Mounts - Pr...

T#:555025

Part#: TDR4680035-01

Ships on Aug 28, 2026

Sale - Save 28% $ 597.46

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

$ 432.64 USD

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Sale - Save 28%

$ 597.46

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

$ 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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OEM Rein Magnetic Differential Oil Drain Plug - M22x1.5 - Most BMW & ...

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:38890943

Part#: HWU0065

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$ 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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Loctite 5970 Gasket/Sealing Compound - 50ml

T#:25772539

Part#: 5970

Ships in 2 Business Days

$ 55.23 USD

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$ 55.23 USD

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This Loctite 5970 Sealant is recommended by BMW to be used to seal the rear differential cover and numerous engine oil pans. Also used for multiple MINI, Audi, and VW applications.

Rear Differential Mounts - OEM/Meyle HD Rubber - E46, X3, Z4 ...

T#:339943

Part#: E46-MY-DIFF

In Stock

$ 88.99

This product was last offered at the strikethrough price on
02-26-2026

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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Premium Differential Service Kit - E46 M3, E9X M3, E82 1 M Coupe ...

Includes BMW SAF-XJ limited slip differential fluid with FM booster

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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$ 301.99

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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Rear Differential Service Kit for various BMW Models

T#:42133544

Part#: 835225790TKT

In Stock

Sale - Save 2% $ 60.99

This product was last offered at the strikethrough price on
08-04-2026

$ 59.72 USD

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08-04-2026

$ 59.72 USD

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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

Differential Service Kit

T#:15710761

Part#: 33117525064-KT

In Stock

Sale - Save 2% $ 100.76

This product was last offered at the strikethrough price on
06-15-2026

$ 98.71 USD

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$ 98.71 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. Kit includes 3 Bottles of Castrol SAF-XJ 75w140 2 Drain plugs

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E46 Finned Differential Cover Upgrade Kit

T#:401688

Part#: 33117512980KT

Ships in 3 Business Days

$ 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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Performance Differential Cover install kit

T#:556968

Part#: 33112282482KT3

Ships on Aug 28, 2026

Sale - Save 7% $ 676.14

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

$ 627.61 USD

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$ 676.14

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

$ 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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Differential Service Kit

T#:15744025

Part#: 331175250640-KT

In Stock

Sale - Save 8% $ 274.99

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

$ 252.18 USD

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$ 252.18 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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Differential Oil Drain Plug

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:27405453

Part#: 33117525064

In Stock

$ 14.99

This product was last offered at the strikethrough price on
08-03-2026

$ 9.99 USD

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$ 9.99 USD

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Rein Differential Drain Plug Gasket

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:19654

Part#: 07119963355

Ships in 4 Business Days

$ 2.03 USD

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$ 2.03 USD

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GASKET RING for various sensors and seals.

Pre-XDrive Transfer Case Service Kit - E46

T#:56616376

Part#: 27111226467KT2

Ships in 3 Business Days

$ 48.99 USD

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$ 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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Limited Slip Differential With Output Shaft Seal - 188 (Small Diff Ho...

T#:55965861

Part#: 30309175WKWVTKT2

Ships on Aug 28, 2026

$ 1,269.99 USD

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$ 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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Elring Differential Input Shaft Seal - 50x80x9mm - BMW E82 1M, E46 M3...

T#:44733256

Part#: 703.190

Special Order: No Guaranteed ETA

$ 34.99 USD

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$ 34.99 USD

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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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Shaft Seal - Differential (Axle Drive)

T#:54852004

Part#: B46.610

Special Order: No Guaranteed ETA

$ 14.99 USD

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$ 14.99 USD

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This OEM-quality replacement shaft seal from Elring is the perfect fix for keeping your gear oil where it belongs.

Front Differential Input Seal Kit - E46, E53, E60, E61, F30

T#:41289766

Part#: 31521428678TKT

Back Ordered

$ 52.99

This product was last offered at the strikethrough price on
07-23-2026

$ 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.

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