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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Genuine BMW - Corporate Logo
T#:1095
Part#: 33117512980
Ships in 3 Business 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#:5958667
Part#: 33108437888
Ships in 5 Business Days
2% off MSRP $ 1,480.00

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

$ 1,450.99 USD
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2% off MSRP
$ 1,480.00

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

$ 1,450.99 USD
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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

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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


Genuine BMW - Corporate Logo
T#:21772
Part#: 24357507706
In Stock at Vendor
$ 104.99

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

$ 70.99 USD
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$ 70.99 USD
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Genuine BMW Speed Sensor -
This item fits the following BMW Chassis:
E39,E46,E53 X5,E83 X3

Genuine BMW - Corporate Logo
T#:1333
Part#: 33112282482
Ships in 3 Business Days
3% off MSRP $ 826.99

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

$ 800.99 USD
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3% off MSRP
$ 826.99

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

$ 800.99 USD
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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

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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.
Genuine BMW - Corporate Logo
T#:107
Part#: 33107514198
Ships in 8 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 Sep 1, 2026
$ 287.99 USD
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$ 287.99 USD
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