Home
Drivetrain
Differential and Gearing Upgrades

BMW Differential and Gearing Upgrades for BMW 3 Series E46 (1999-2005)

Clear BMW chassis

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.

Sub-Categories

Sort By:

OEM BMW Rear Differential Mount - E46, E83 X3, E85 Z4

We Price Match - Give Us A Call or Chat!

T#:12525

Part#: 33176751808

In Stock

$ 44.99

This product was last offered at the strikethrough price on
04-18-2026

$ 27.99 USD

Add to Wish List

Qty

$ 27.99 USD

Add to Wish List

RUBBER MOUNTING REAR:331020

Differential Input Shaft Seal - Priced Each

T#:44021076

Part#: 33121213949

Ships in 2 Business Days

$ 27.99

This product was last offered at the strikethrough price on
05-07-2026

$ 26.99 USD

Add to Wish List

Qty

$ 26.99 USD

Add to Wish List

URO Differential Cover for E46 M3

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

T#:37993429

Part#: 33112282482

In Stock

$ 241.99 USD

Add to Wish List

Qty

$ 241.99 USD

Add to Wish List

Differential bushing failure is a common weak point of the E46 M3. Bushings are not sold separately, you will need the whole rear cover.

Driveshaft Seal

T#:594925

Part#: 31507609535

In Stock

$ 9.99 USD

Add to Wish List

Qty

$ 9.99 USD

Add to Wish List

Seals the driveshaft to the differential

Corteco Output Shaft Seal

T#:583459

Part#: 33107505604

In Stock

$ 14.42

This product was last offered at the strikethrough price on
07-06-2026

$ 11.99 USD

Add to Wish List

Qty

$ 11.99 USD

Add to Wish List

Seals the axles into the differential

SKF Seal - Differential Pinion Shaft (50 X 80 X 9 mm)

T#:588869

Part#: 33121213949

Ships in 1-2 days

$ 17.99 USD

Add to Wish List

Qty

$ 17.99 USD

Add to Wish List

URO Differential Output Shaft Seal W/ Lock Ring - BMW E36 E46 E53 E60...

2X Entries For Our G87 M2 Sweepstakes!

T#:43750219

Part#: 33107505604

In Stock

$ 10.00

This product was last offered at the strikethrough price on
08-13-2026

$ 9.98 USD

Add to Wish List

Qty

$ 9.98 USD

Add to Wish List

Maintaining a proper amount of fluid in the rear differential is vital to the performance and longevity of the differential. If a leaking shaft seal is left untouched, the results could be catastrophic. Two seals required per vehicle.

Show More Show Less

Billet Diff Cover Replacement Drain Plug

T#:19362530

Part#: 4835K45

In Stock

Sale - Save 15% $ 6.99

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

$ 5.93 USD

Add to Wish List

Qty

Sale - Save 15%

$ 6.99

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

$ 5.93 USD

Add to Wish List

Extreme-Pressure Steel Plug With Hex Drive - Fluoroelastomer Rubber Gasket, 9/16"-18 UN/UNF Thread

Differential Input Shaft Seal - Priced Each

T#:49335120

Part#: 33121213949

In Stock

$ 18.99

This product was last offered at the strikethrough price on
07-27-2026

$ 15.99 USD

Limited Qty Sale

Add to Wish List

Qty

$ 18.99

This product was last offered at the strikethrough price on
07-27-2026

$ 15.99 USD

Limited Qty Sale

Add to Wish List

Replaces cracked or hardened valve body seals

Front Differential Input Shaft Seal

T#:594926

Part#: 31521428678

Ships in 2 Business Days

$ 17.99 USD

Add to Wish List

Qty

$ 17.99 USD

Add to Wish List

Seals the input shaft flange to the front differential

Febi Drain Plug Gasket

We Price Match - Give Us A Call or Chat!

T#:340702

Part#: 07119963355

Ships on Oct 6, 2026

$ 1.99 USD

Add to Wish List

Qty

$ 1.99 USD

Add to Wish List

22x27 aluminum sealing ring

Select Vehicle

Purpose

Replacement (11)

Category

Differential and Gearing Upgrades

Brand

Price

Special Offers

On Sale (1)

Shipping