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BMW Differential and Gearing Upgrades

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.

ECS Magnetic Differential Oil Drain Plug
ECS Magnetic Differential Oil Drain Plug
You use a magnetic drain plug for your engine oil, right?...
ECS - Corporate Logo
T#:366828
Part#: 009314ECS01A
In Stock
$25.95
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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.
Differential Drain Plug with O-Ring - Most BMWs
Differential Drain Plug with O-Ring - Most BMWs
This is the front or rear Genuine BMW differential fluid ...
Genuine BMW - Corporate Logo
T#:7923
Part#: 33117525064
In Stock
$6.98
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This is the front or rear Genuine BMW differential fluid drain plug for many BMWs. This can also be the transfer case plug or automatic transmission plug on some BMWs.

+ Year & Model Applications
(click to expand)
This item fits the following BMWs:
1970-1976 2002 BMW 1600 2002 2002tii
2008+ E82 BMW 128i 135i 1M Coupe
1977-1983 E21 BMW 320i 323i
1984-1991 E30 BMW 318i 318is 318ic 325e 325es 325i 325ic 325is 325ix M3
1992-1998 E36 BMW 318i 318is 318ti 318ic 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi M3
2006-2011 E90 BMW 325i 325xi 328i 328xi 328i xDrive 330i 330xi 335d 335i 335xi 335i xDrive M3 - Sedan
2006-2012 E91 BMW 325xi 328i 328xi 328i xDrive - Wagon
2007-2012 E92 BMW 328i 328xi 328i xDrive 335i 335is 335xi 335i xDrive M3 - Coupe
2007-2012 E93 BMW 328i 335i M3 - Convertible
1976-1981 E12 BMW 528i 530i
1982-1988 E28 BMW 524td 528e 533i 535i 535is M5
1989-1995 E34 BMW 525i 530i 535i 540i M5
1997-2003 E39 BMW 525i 528i 530i 540i M5
2004-2010 E60 BMW 525i 525xi 530i 530xi 528i 528xi 528i xDrive 535i 535xi 535i xDrive 545i 550i M5
2010+ F07 BMW 535i GT, 535i xDrive GT, 550i GT, 550i xDrive GT
2011+ F10 BMW 528i 528i xDrive 535i 535i xDrive 550i 550i xDrive M5
1982-1989 E24 BMW 633csi 635csi M6
2004-2010 E63 BMW 645ci 650i M6
2012+ F12 BMW 640i 650i
1981-1987 E23 BMW 733i 735i
1988-1994 E32 BMW 735i 735il 740i 740il 750il
1995-2001 E38 BMW 740i 740il 750il
2002-2008 E65 BMW 745i 745li 750i 750li 760i 760li
2009+ F01 BMW 740i 740li 750i 750li 750i xDrive 750li xDrive 760li
1990-1999 E31 BMW 840i 840ci 850i 850ci 850csi
2004-2010 E83 BMW X3 2.5i X3 3.0i X3 3.0si
2011+ F25 BMW X3 xDrive28i X3 xDrive35i
2000-2006 E53 BMW X5 3.0i X5 4.4i X5 4.6is X5 4.8is
2007-2013 E70 BMW X5 3.0si X5 4.8i X5 xDrive30i X5 xDrive35d X5 xDrive35i X5 xDrive48i X5M
2008+ E71 BMW X6 xDrive35i X6 xDrive50i X6M
1997-2002 Z3 BMW Z3 1.9 Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0i M Roadster M Coupe
2003-2008 E85 BMW Z4 2.5i Z4 3.0i Z4 3.0si Z4 M Roadster M Coupe
2009+ Z4 BMW Z4 sDrive30i Z4 sDrive35i Z4 sDrive35is
2000-2003 E52 BMW Z8 Roadster

Genuine BMW Differential Plug Gasket, 22x27 - 07119963355
Genuine BMW Differential Plug Gasket, 22x27 - 07119963355
When servicing the rear axle and differential, it is alwa...
Genuine BMW - Corporate Logo
T#:348476
Part#: 07119963355
In Stock
$1.00
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When servicing the rear axle and differential, it is always best to replace this sealing washer to prevent any potential leaks from forming.

E46, Z4 High Performance Finned Differential Cover
E46, Z4 High Performance Finned Differential Cover
This aluminum diff cover is off the Z4 Roadster and featu...
Genuine BMW - Corporate Logo
T#:1095
Part#: 33117512980
In Stock
26% off MSRP $194.13
$142.79
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26% off MSRP $194.13
$142.79
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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)

Differential Input Shaft Seal - E82 E46 E9X E39 E60 Z4
Differential Input Shaft Seal - E82 E46 E9X E39 E60 Z4
Replace your leaking differential input seal with this Ge...
Genuine BMW - Corporate Logo
T#:7924
Part#: 33121213949
In Stock
35% off MSRP $57.38
$37.19
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35% off MSRP $57.38
$37.19
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Replace your leaking differential input seal with this Genuine BMW part. Whenever service is performed on the differential it is a good idea to check / replace any seals. This seal measures 50mm X 80mm X 9mm. We also recommend you replace the securing plate # 33121205138 at the same time.

This item fits the following BMWs:
2011 E82 BMW 1M Coupe
2001-2006 E46 BMW M3
2008-2011 E90 BMW M3 - Sedan
2008-2013 E92 BMW M3 - Coupe
2008-2013 E93 BMW M3 - Convertible
1988 E28 BMW M5
1991-1995 E34 BMW 540i M5
1999-2003 E39 BMW M5
2006-2010 E60 BMW i M5
2011+ F10 BMW M5
1987-1989 E24 BMW M6
2006-2010 E63 BMW M6
2012+ F12 BMW M6
2013+ F06 BMW M6 Gran Coupe
1988-1994 E32 BMW 740i 740il 750il
1990-1999 E31 BMW 840i 840ci 850i 850ci 850csi
2006-2008 E85 BMW Z4 M Roadster M Coupe
BMW Motorsport Ring & Pinion Gear Set (R&P only) - 3.85 - E46 M3, E60 M5, E63 M6
BMW Motorsport Ring & Pinion Gear Set (R&P only) - 3.85 - E4...
Hands down - one of the best performance upgrades you can...
Genuine BMW Motorsport - Corporate Logo
T#:402875
Part#: 33108311351
In Stock
$998.95
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Hands down - one of the best performance upgrades you can make to an E46 M3, E60 M5 or E63/E64 M6! With almost no downside you can make your BMW much quicker by swapping in a new ring & pinion gear set. The gearing used to be overlooked when planning modifications but the 3.85, 3.91, and 4.10 gears are now one of our biggest selling upgrades for the E46 M3! With a rear end gear upgrade you get the effects of adding horsepower but without adding any more stress to the engine or drivetrain. It's one of the best areas to get return from your modification spending. Using a shorter (numerically higher) gear ratio will give you better acceleration. The R&P acts as a torque multiplier, putting the engine into the power band sooner for each gear. There is an 6% increase in torque at the wheels with the shorter R&P. Want to make your car faster off the line or out of corners? Or avoid a downshift to pass on the highway? This is what you need.

The R&P can be installed on its own but for cars that have more than 60,000 miles it would be a better idea to rebuild the whole diff. The factory viscous limited slip units have a typical lifespan of 50-70,000 miles. We offer diff rebuilding with 3.85 or other gear options and you get a fully-rebuilt and serviced limited slip unit at the same time. Click here for our diff rebuild options.

3.85 Gearing Example: 2004 M3, 6-speed manual, 275/35-19" rear tires

Gear RatioGearSpeedRPM

40 MPH in 4th
3.62 4th 40mph 2,250rpm
3.85 4th 40mph 2,350rpm

70 MPH Cruise
3.62 6th 70mph 2,650rpm
3.85 6th 70mph 2,800rpm

5th Gear Speed at Redline
3.62 5th 175mph 8,000rpm
3.85 5th 165mph 8,000rpm

Why 5th? Because 6th does not have the mechanical advantage to get past wind resistance at these speeds - it is more of a cruise/overdrive gear. Using 5th 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.


This item is the genuine BMW part and the ring & pinion set only. You will need to have this professionally installed into your existing differential. BMW does not supply differential rebuild parts (bearings, shims, plates, etc.) so only a qualified shop that is experienced in BMW diff rebuilding should perform this installation. We also offer built differentials and exchanges, click here.

This item fits the following BMWs:
2001-2006 E46 BMW M3
2004-2010 E60 BMW M5
2004-2011 E63 BMW M6

OEM part number 33108311351


Differential Cover Gasket - E30 E28 E24 E23
Differential Cover Gasket - E30 E28 E24 E23
This is the differential cover gasket / diff seal for E30...
Genuine BMW - Corporate Logo
T#:1300
Part#: 33111210405
In Stock
$5.56
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This is the differential cover gasket / diff seal for E30 3 series, 1984-1991.
E46 M3 Stock Differential Cover With Bushings
E46 M3 Stock Differential Cover With Bushings
BMW does not sell the differential mounts separate from t...
Genuine BMW - Corporate Logo
T#:1333
Part#: 33112282482
In Stock
19% off MSRP $225.44
$181.95
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19% off MSRP $225.44
$181.95
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BMW does not sell the differential mounts separate from the cover. And as with all rubber mounts, they will have to be replaced at some point, forcing you to also buy a new diff cover. This is an Original BMW part.
**Note** - a paper gasket is not sold with this cover. BMW no longer uses paper gaskets - they advise the use of a silicone sealant such as RTV black.

Applications:
2001-2006 E46 M3, M3 CSL, coupe and convertible


Finned Rear Differential Cover - 33112228336 - E36 Z3M S54 S52
Finned Rear Differential Cover - 33112228336 - E36 Z3M S54 S52 ...
An OE replacement for your leaking or damaged rear differ...
Genuine BMW - Corporate Logo
T#:394453
Part#: 33112228336
In Stock
25% off MSRP $601.36
$449.50
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25% off MSRP $601.36
$449.50
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An OE replacement for your leaking or damaged rear differential cover.

Fits the following BMW's:
E36 BMW Z3 S54 & S52


Ring & Pinion Gear Set (R&P only) - 4.10 - E46 M3, E60 M5
Ring & Pinion Gear Set (R&P only) - 4.10 - E46 M3, E60 M5 ...
If there was a Top 5 list of things to do on the E46 M3, ...
Genuine BMW Motorsport - Corporate Logo
T#:21503
Part#: TMS21503
In Stock
5% off MSRP $946.61
$899.28
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5% off MSRP $946.61
$899.28
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If there was a Top 5 list of things to do on the E46 M3, a shorter gears would be in the top two... The gearing used to be overlooked when planning modifications but the 3.91 and 4.10 gears are now one of our biggest selling upgrades for the E46 M3! With a rear end gear upgrade you get the effects of adding horsepower but without adding any more stress to the engine or drivetrain. The R&P acts as a torque multiplier, getting you into the power band sooner in each gear. It's one of the best areas to get return from your modification spending. The shorter (numerically higher) rear end gears will give you better acceleration in all gears at any speed with few downsides. Want to make your car faster off the line or out of corners? Or avoid a downshift to pass on the highway? This is what you need. This 4.10 is the latest version from BMW Motorsport - shot peened and hardend for increased strength. The R&P can be installed on its own but for cars that have more than 60,000 miles it would be a better idea to rebuild the whole diff. The factory viscous limited slip units have a typical lifespan of 50-70,000 miles. We offer diff rebuilding with 4.10 or other gear options and you get a fully-rebuilt and serviced limited slip unit at the same time. Click here for our diff rebuild options.

4.10 Gearing Example: 2004 M3, 6-speed manual, 275/35-19" rear tires

Gear RatioGearSpeedRPM

40 MPH in 4th
3.62 4th 40mph 2,250rpm
4.10 4th 40mph 2,550rpm

70 MPH Cruise
3.62 6th 70mph 2,650rpm
4.10 6th 70mph 3,000rpm

5th Gear Speed at Redline
3.62 5th 175mph 8,000rpm
4.10 5th 154mph 8,000rpm

Why 5th? Because 6th does not have the mechanical advantage to get past wind resistance at these speeds - it is more of a cruise/overdrive gear. Using 5th 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.


This item is the genuine BMW part and the ring & pinion set only. You will need to have this professionally installed into your existing differential. BMW does not supply differential rebuild parts (bearings, shims, plates, etc.) so only a qualified shop that is experienced in BMW diff rebuilding should perform this installation. We also offer built differentials and exchanges, click here.

This item fits the following BMWs:
2001-2006 E46 BMW M3
2004-2010 E60 BMW M5 (manual transmission only)

OEM part number 33108321899

Speedometer Sensor - Mounted in Differential - E36 Z3 E30 325IX
Speedometer Sensor - Mounted in Differential - E36 Z3 E30 325IX ...
This Genuine BMW speedometer / pulse generator is mounted...
Genuine BMW - Corporate Logo
T#:14056
Part#: 62168357020
In Stock
19% off MSRP $38.32
$30.93
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19% off MSRP $38.32
$30.93
Free Shipping on orders $99 and up
This Genuine BMW speedometer / pulse generator is mounted in the back of the differential and provides wheel speed information to the instrument cluster speedometer.

This item fits the following BMWs:
1987-1991 E30 BMW 325ix
1992-1998 E36 BMW 318i 318is 318ti 318ic 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1990-1999 E31 BMW 840i 840ci 850i 850ci 850csi
1996-2002 Z3 BMW Z3 1.9 Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0i
Genuine BMW Driveshaft Seal 33107609536
Genuine BMW Driveshaft Seal 33107609536
This seal is found where the driveshaft connects to the d...
Genuine BMW - Corporate Logo
T#:20830
Part#: 33107609536
In Stock
13% off MSRP $14.72
$12.81
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13% off MSRP $14.72
$12.81
Free Shipping on orders $99 and up

This seal is found where the driveshaft connects to the differential.

Genuine BMW Shaft Seal - 50X78X10/15

This item fits the following BMW Chassis:
E70 X5M,E71 X6M,E53 48IS,E38,E39,E53 X5,E63,E65,E70 X5,E71 X6,E82,E89 Z4,E90,E92,E93,F01,F02,F06,F10,F12,F13,F15,F16,F22,F30,F32,F33,F36



Output Shaft Seal E36 M3, E39, E46
Output Shaft Seal E36 M3, E39, E46
Output Shaft Seal E36 M3, E39, E46 - does not fit E46 M3....
Rein - Corporate Logo
T#:2756
Part#: 23111224799
In Stock
$12.95
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Output Shaft Seal E36 M3, E39, E46 - does not fit E46 M3. this is the seal that is on the output side of the transmission.

This item fits the following BMWs:
1992-1998 E36 BMW 328i 328is 328ic M3
1999-03/2003 E46 BMW 328i 328ci 330i 330ci
1997-2003 E39 BMW 525i 528i 530i
1997-2002 Z3 BMW Z3 2.8 Z3 3.0i M Roadster M Coupe
Speedometer Sensor - Mounted in Differential - E30 E24 Z3
Speedometer Sensor - Mounted in Differential - E30 E24 Z3
This Genuine BMW speedometer / pulse generator is mounted...
Genuine BMW - Corporate Logo
T#:10803
Part#: 62168355008
In Stock
15% off MSRP $55.61
$47.24
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15% off MSRP $55.61
$47.24
Free Shipping on orders $99 and up
This Genuine BMW speedometer / pulse generator is mounted in the back of the differential and provides wheel speed information to the instrument cluster speedometer. We also recommend getting the seal for the sensor #33111210739.

This item fits the following BMWs:
1988-1991 E30 BMW 318i 318is 318ic 325e 325es 325i 325ic 325is M3
7/1987-1989 E24 BMW 635csi M6
1997 Z3 BMW Z3 2.8
1998-2002 Z3 BMW M Roadster M Coupe
E9X M3 6MT Differential Upgrade - Custom Options
E9X M3 6MT Differential Upgrade - Custom Options
A custom differential is one of the best upgrades to have...
Turner Motorsport - Corporate Logo
T#:339945
Part#: TMS20540
Available
$2,952.95
Starting at $2,952.95
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$2,952.95
Starting at $2,952.95
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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. Use the chart below for examples of the differences.



2009 M3, 6-speed manual, 265/35-19" rear tires

(click to expand)

Gear RatioGearSpeedRPM

4th Gear @ 40 MPH

3.854th40 MPH2,350 RPM

4.104th40 MPH2,500 RPM

4.454th40 MPH2,700 RPM

70 MPH Cruise

3.856th70 MPH3,000 RPM

4.106th71 MPH3,250 RPM

4.456th71 MPH3,500 RPM

5th Gear Speed at Redline

3.855th168 MPH8,250 RPM

4.105th157 MPH8,250 RPM

4.455th145 MPH8,250 RPM

Why 5th? Because 6th does not have the mechanical advantage to get past wind resistance at these speeds - it is more of a cruise/overdrive gear. Using 5th 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 3.85 gearing must be sent in*