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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ECS - Corporate Logo
T#:378193
Part#: 002447ECS03KT
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Worn rubber differential mounts will lead to the differential twisting and shifting around in the rear subframe. Not only will this be noisy but it's bad for driver confidence and bad for the chassis as well. Even on fresh rubber bushings the differential has deflection and twist, especially if the car has been modified for more torque. Since the differential is centrally mounted in the rear subframe, with all suspension mounts interconnected, a differential with too much deflection will affect handling and could even damage the rear subframe.

These 88A urethane E46 M3 diff mounts are much stiffer than stock but still not as solid as our Turner aluminum/Delrin bushings. This set will resist twisting much better than the stock rubber mounts. Included is the front diff mount and two rear mounts in the cover.

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Team MFactory Helical Limited Slip Differential (LSD) - Final Ratio 3...
For vehicles with manual or automatic transmission (Gear ratio=3.15:1)
Team MFactory - Corporate Logo
T#:379412
Part#: MF-TRS-05E46A
In Stock
$ 999.99 USD
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$ 999.99 USD
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The best way to gain a prominent advantage over the competition is to do it with the MFactory Helical Limited Slip Differential. The smooth consistent distribution of power to the wheels with the MFactory Helical LSD puts the power to the ground and maximizes your vehicle's traction. A must for any car be it street, strip, or track. What exactly does an LSD do you ask? well without an LSD your car is actually 1 wheel drive, in that it can't supply torque to both wheels at the same time and will only supply torque to the wheel with less grip, which is what the shortfall is to an open differential (what most vehicles have). An LSD only lets the wheels spin at different speeds by a limited amount (typically this is a percentage difference) which is when the differential locks and both wheels get power. This is not how locked differentials work such as in off road trucks which supply equal torque and rotational speed to both rear wheels at the same time, which can cause issues with handling.
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Metal Plate Limited-Slip Differential - 1.5/2.0 Way, V2
For vehicles with an automatic or manual transmission with a Final Gear Ratio of 3.15 ...
Team MFactory - Corporate Logo
T#:379410
Part#: MF-TRS-10E90B
Back Ordered
$ 999.99 USD
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$ 999.99 USD
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The best way to gain a prominent advantage over the competition is to do it with the MFactory Metal Plate Limited Slip Differential. The smooth consistent distribution of power to the wheels with the MFactory Plate LSD puts the power-to-the-ground and maximises your vehicle's traction. This 2-way differential will provide torque transfer during both acceleration and deceleration. This means that regardless of whether there is load (throttle) being applied to the differential or not, it will lock up during slippage. Ideal for those with track use in mind. What exactly does an LSD do you ask? Well without an LSD your car is actually 1 wheel drive, in that it can't supply torque to both wheels at the same time and will only supply torque to the wheel with less grip, which is what the shortfall is to an open differential (what most vehicles have). An LSD only lets the wheels spin at different speeds by a limited amount (typically this is a percentage difference) which is when the differential locks and both wheels get power. This is not how locked differentials work such as in off road trucks which supply equal torque and rotational speed to both rear wheels at the same time, which can cause issues with handling. Features: Forged and Cryo-Tempered for unsurpassed toughness Advanced Shot Peening technology for increased surface hardness Coil Spring preload system ensures minimal power loss and maximum response Lower initial pressure ensures maximum durability and chatter-free operation Fully rebuildable with adjustable lock (80-100%) and option for different cam types Available in 1.0, 1.5, and 2.0 way options
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ECS - Corporate Logo
T#:378192
Part#: 002447ECS02KT
In Stock
Sale - Save 25% $ 183.99

This product was last offered at the strikethrough price on
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$ 137.99 USD
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Sale - Save 25%
$ 183.99

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

$ 137.99 USD
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Worn rubber differential mounts will lead to the differential twisting and shifting around in the rear subframe. Not only will this be noisy but it's bad for driver confidence and bad for the chassis as well. Even on fresh rubber bushings the differential has deflection and twist, especially if the car has been modified for more torque. Since the differential is centrally mounted in the rear subframe, with all suspension mounts interconnected, a differential with too much deflection will affect handling and could even damage the rear subframe.

These 88A urethane E46 diff mounts are much stiffer than stock but still not as solid as our Turner aluminum/Delrin bushings. This set will resist twisting much better than the stock rubber mounts. Included are the two front diff mounts and the rear mount in the cover.

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ECS - Corporate Logo
T#:348998
Part#: 002447ECS01
In Stock
Sale - Save 25% $ 148.99

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

$ 111.74 USD
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Sale - Save 25%
$ 148.99

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

$ 111.74 USD
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Revitalize your driving experience with ECS Tuning's In-House Engineered Performance Polyurethane Differential Bushings. Say goodbye to soft factory rubber bushings and their deflection. These innovative bushings provide a substantial improvement in the connection between your right foot, the chassis, and the wheels. The outcome is a crisper power transfer from the differential to the wheels, resulting in enhanced throttle control for various driving activities. Notably, these polyurethane bushings achieve these benefits without the harshness or vibration often linked to delrin or solid differential mounts.

Manufactured using a robust 88A durometer polyurethane and a black anodized 6061-T6 aluminum sleeve, these bushings offer superior resistance to chemicals, ozone degradation, road salt, and general wear and tear. This translates to an extended service life.

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Team MFactory Metal Plate Limited-Slip Differential (LSD) - 1.5 Way -...
For vehicles with an automatic or manual transmission with a Final Gear Ratio of 3.15 ...
Team MFactory - Corporate Logo
T#:379408
Part#: MF-TRS-10E90A
Ships in 8 Business Days
$ 999.99 USD
Free Shipping
$ 999.99 USD
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The best way to gain a prominent advantage over the competition is to do it with the MFactory Metal Plate Limited Slip Differential. The smooth consistent distribution of power to the wheels with the MFactory Plate LSD puts the power to the ground and maximizes your vehicle's traction. This 1.5-way differential works similarly to a 2-way in that it provides torque transfer during both acceleration and deceleration. However, the advantage over a 2-way is that it requires less force to lock the differential. This means that it will allow for different wheel speeds, like when cornering. A 1.5-way differential is typically the best option for track or street use, as it keeps from having one tire skipping or dragging.
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Revshift - Corporate Logo
T#:582011
Part#: PDBE46MGREEN
Ships in 3 Business Days
$ 109.99 USD
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Revshift polyurethane differential bushings completely replace the OEM rubber bushings on the E46 M3 and Z4M. These bushings stiffen the differential, improving the vehicle's handling capabilities and eliminating drive-line slop.
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Powerflex - Corporate Logo
T#:378993
Part#: PFR5-4625X2
In Stock
$ 94.99 USD
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$ 94.99 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 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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Genuine BMW - Corporate Logo
T#:370652
Part#: E46M3DIFSER
In Stock
$ 236.99

This product was last offered at the strikethrough price on
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Genuine BMW - Corporate Logo
T#:1095
Part#: 33117512980
Ships in 1-2 days
1% off MSRP $ 280.76

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

$ 277.63 USD
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1% off MSRP
$ 280.76

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

$ 277.63 USD
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This aluminum diff cover is off the Z4 Roadster and features fins on the underside for improved cooling. This is an absolute must for any E46 that sees track time, especially with an LSD installed. This is a direct bolt-on with the existing bolts and all drain and fill plugs transfer over as well. BMW recommends sealing the cover to the diff with black RTV silicone (no gasket).

This item fits the following BMWs:
1999-2006 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi (upgrade!)
2003-2008 E85 BMW Z4 2.5i Z4 3.0i Z4 3.0si (replacement)
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Genuine BMW - Corporate Logo
T#:59552
Part#: 33137840563
Ships in 1-2 days
1% off MSRP $ 189.99

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

$ 188.99 USD
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1% off MSRP
$ 189.99

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

$ 188.99 USD
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Genuine BMW Drive Flange, Output, Left
This item fits the following BMW Chassis:
E46 M3,E85 Z4M,E46,E85 Z4,E86 Z4

Premium Differential Service Kit - E46 M3, E9X M3, E82 1 M Coupe ...
10X Entries Into Our F80 M3 Sweepstakes
Includes BMW SAF-XJ limited slip differential fluid with FM booster
Packaged by Turner - Corporate Logo
T#:598688
Part#: E46M3DIFSERTMSKT
In Stock
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This product was last offered at the strikethrough price on
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$ 286.01 USD
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Sale - Save 5%
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This product was last offered at the strikethrough price on
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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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ECS - Corporate Logo
T#:378219
Part#: 002447ECS04KT
In Stock
Sale - Save 25% $ 112.99

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

$ 84.74 USD
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Sale - Save 25%
$ 112.99

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

$ 84.74 USD
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Your rear differential is indirectly connected to your right foot through the engine and driveline, and connected to the seat of your pants through the chassis. Soft factory rubber differential bushings absorb vibrations between chassis and differential, providing comfort and softness in both of these connections.

Enter ECS Tuning's In-House Engineered Performance Polyurethane Differential Bushings. By eliminating the deflection factory rubber bushings permit, the connection between your right foot (and your seat) to the wheels is improved. Removal of this slop allows for crisper power transfer from differential to wheels, which means better throttle control while carving a canyon road, drag racing, sliding the rear end out, or just driving to work. This is achieved without the harshness or vibration associated with delrin or solid differential mounts.

Featuring a tough 88A durometer polyurethane and Black anodized 6061-T6 aluminum Sleeve, our Performance Polyurethane Differential Bushings are more resistant to chemicals, ozone degradation, road salt, and general wear and tear than factory rubber bushings, resulting in a longer service life.

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Revshift - Corporate Logo
T#:1105905
Part#: PDB-E4695A
Special Order: No Guaranteed ETA
$ 129.99 USD
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$ 129.99 USD
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Utilizing high-precision machining technologies and their very own Polyurethane Manufacturing Department, every Revshift product is designed, manufactured, and tested in-house at their Detroit, Michigan facility.
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Powerflex Black Series - Corporate Logo
T#:379935
Part#: PFR5-4625BX2
Ships in 2 Business Days
$ 107.99 USD
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$ 107.99 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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OS Giken - Corporate Logo
T#:1387
Part#: BM237-HA
Ships on Oct 14, 2026
$ 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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Genuine BMW - Corporate Logo
T#:172491
Part#: 83300495143
Ships in 1-2 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.
Team MFactory - Corporate Logo
T#:379403
Part#: MF-TRS-05E39
Back Ordered
$ 999.99 USD
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$ 999.99 USD
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Allows for traction at all times by providing the most power to the wheel with more grip. Unlike plate differentials (1,1.5,2-way) helical LSDs can supply different spin rates to each axle, like when cornering.
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OS Giken - Corporate Logo
T#:34382134
Part#: LSD-TUNE
Ships in 3 Business Days
$ 150.00 USD
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$ 150.00 USD
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Genuine BMW - Corporate Logo
T#:107
Part#: 33107514198
Ships in 7 Business Days
$ 2,680.99 USD
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$ 2,680.99 USD
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Price includes $100.00 core charge.

Genuine BMW - Corporate Logo
T#:1002353
Part#: E46M3DIFSER1KT
Ships on Feb 26, 2027
$ 287.99

This product was last offered at the strikethrough price on
09-03-2026

$ 272.99 USD
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$ 272.99 USD
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