Turner Custom Limited Slip Differentials - E9X M3

A custom differential is one of the best upgrades to have done to your BMW. Not only can you get more performance but you can also get rid of the open diff in non M BMWs or M Variable limited slip diff. It's easy to forget about the rear axle when you're considering performance upgrades but changing the gearing is in the top 3 things to do to make the car faster. A custom diff is also a rebuilt unit with new seals, bearings, and limited slip unit.
Sort By:

E9X M3 6MT Differential Upgrade - Custom Options
Diffs by Turner - Corporate Logo
T#:339945
Part#: TMS20540
Back Ordered, No ETA
Starting at $2,999.00
Free Shipping
Starting at $2,999.00
Free Shipping
A custom differential is one of the best upgrades to have done to your E90 or E92 M3. Not only can you get more performance but you can also address the weak points in the M Variable limited slip diff. It's easy to forget about the rear axle when you're considering performance upgrades but changing the gearing is in the top 3 things to do to make the car faster. A custom diff is also a rebuilt unit with new seals, bearings, and limited slip unit. Gearing The E9X M3 gearing depends on which transmission/clutch spec your car has - 6MT or the DCT. The manual transmission cars have a relatively short 3.85 gear ratio on manual transmission cars. They could use a shorter gear because the engine redline is so high - the car has a long power band and the gear spacing allows you to stay well within that range. But there's always more acceleration to be had with a shorter gear set and we have quite a few to choose from for either transmission. Your speed vs RPM obviously changes with a different gear set. Limited Slip Options The M3's M Variable locking differential is genius when it's working properly. Unfortunately, as many M3 owners have come to find, the system only has a service life of 80,000 miles (sometimes less) and then the viscous unit inside starts to fail (is your's clunking?). We can rebuild the internals and bring it back to a perfectly-functioning viscous M Variable unit. Or you may choose to lose the variable lock in favor of a traditional clutch-type or helical diff with a set locking. We also build diffs with Quiafe, Kaaz, and OS Giken (favorite of the Turner racing team) limited slip units. Core Charge. If we are building a diff from our own stock a refundable core charge will apply until we get your original diff back. You have a maximum of 30 days from the time you receive the diff to send it back us for a refund. This item fits the following BMWs: 2008-2011 E90 BMW M3 6MT - Sedan 2008-2013 E92 BMW M3 6MT - Coupe 2008-2013 E93 BMW M3 6MT - Convertible
Show More Show Less
E9X M3 DCT Differential Upgrade - Custom Options
Diffs by Turner - Corporate Logo
T#:340269
Part#: TMS213596
Direct Ship, Expected Ship Date: Jun 29, 2021
Starting at $2,999.00
Free Shipping
Starting at $2,999.00
Free Shipping


A custom differential is one of the best upgrades to have done to your E90 or E92 M3. Not only can you get more performance but you can also address the weak points in the M Variable limited slip diff. It's easy to forget about the rear axle when you're considering performance upgrades but changing the gearing is in the top 3 things to do to make the car faster. A custom diff is also a rebuilt unit with new seals, bearings, and limited slip unit.

Gearing The E9X M3 gearing depends on which transmission/clutch spec your car has - 6MT or the DCT. The DCT comes with a taller 3.15 gear set (taller than the 3.85 used in the manual transmission cars) to make up for the different transmission ratios and the additional 7th gear. But there's always more acceleration to be had with a shorter gear set and we have quite a few to choose from for either transmission. Your speed vs RPM obviously changes with a different gear set. Use the chart below for examples of the differences.



2009 M3, 7-speed DCT, 265/35-19" rear tires

(click to expand)

Gear RatioGearSpeedRPM

4th Gear @ 40 MPH

3.154th41 MPH2,750 RPM

3.624th39 MPH3,000 RPM

70 MPH Cruise

3.157th70 MPH2,800 RPM

3.627th70 MPH3,250 RPM

6th Gear Speed at Redline

3.156th171 MPH8,250 RPM

3.626th149 MPH8,250 RPM

Why 6th? Because 7th does not have the mechanical advantage to get past wind resistance at these speeds - it is more of a cruise/overdrive gear. Using 6th for comparison purposes is much more relevant than having to take into account wind direction, resistance, grade, elevation, tire sizing, etc. These numbers are for comparisons among gear ratios only, not to determine what your M3 will top out at.
Limited Slip Options The M3's M Variable locking differential is genius when it's working properly. Unfortunately, as many M3 owners have come to find, the system only has a service life of 80,000 miles (sometimes less) and then the viscous unit inside starts to fail (is your's clunking?). We can rebuild the internals and bring it back to a perfectly-functioning viscous M Variable unit. Or you may choose to lose the variable lock in favor of a traditional clutch-type or helical diff with a set locking. We also build diffs with Quiafe, Kaaz, and OS Giken (favorite of the Turner racing team) limited slip units.

Core Charge. If we are building a diff from our own stock a refundable core charge will apply until we get your original diff back. You have a maximum of 30 days from the time you receive the diff to send it back us for a refund. Click here for more detail and explanation of the core charge.

*For full core deposit return, factory diff with 3.15 gearing must be sent in*

FAQ: For a full FAQ on the custom diff process, click here.

This item fits the following BMWs:
2008-2011 E90 BMW M3 DCT - Sedan
2008-2013 E92 BMW M3 DCT - Coupe
2008-2013 E93 BMW M3 DCT - Convertible

Show More Show Less
Powerflex Polyurethane Rear Differential Rear Position Bushing Set - E82 1M E9x M3
Powerflex - Corporate Logo
T#:376418
Part#: PFR5-1226
In Stock
$50.32
Free Shipping
$50.32
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. 

Show More Show Less

Race Polyurethane Differential Bushing, Rear Position - E8X, E9X
Powerflex Black Series - Corporate Logo
T#:376534
Part#: PFR5-1226B
Direct Ship, Expected Ship Date: Jun 24, 2021
$48.99
$48.99

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

Show More Show Less

Powerflex Performance Polyurethane Rear Differential Bushing Set - Front Position - E9x F3X F2X E8X
Powerflex - Corporate Logo
T#:376480
Part#: PFR5-425X2
In Stock
$98.99
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. 

Engineered to perform, Powerflex performance polyurethane differential 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. 

Show More Show Less
Powerflex Race Polyurethane Rear Differential Bushing Set - Front Position - E9x F3X F2X E8X
Powerflex Black Series - Corporate Logo
T#:376381
Part#: PFR5-425BX2
In Stock
$108.99
Free Shipping on orders $49 and up

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. 

Show More Show Less

ECS Magnetic Differential Oil Drain Plug - Most BMW & Mini Models
ECS - Corporate Logo
T#:366828
Part#: 009314ECS01A
In Stock
Sale - Save 15% $34.95
$29.71
Free Shipping on orders $49 and up
Sale - Save 15% $34.95