Home
Drivetrain
Differential and Gearing Upgrades

BMW Differential and Gearing Upgrades for BMW Z Series E85/6 (2003-2008)

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:

Genuine BMW Front Axle Hexagon Screw With Flange 31106772199 ...

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:12469

Part#: 31106772199

In Stock

$ 7.99 USD

Add to Wish List

Qty

$ 7.99 USD

Add to Wish List

GENUINE BMW HEXAGON SCREW WITH FLANGE:319500

Genuine BMW Rear Axle Hex Bolt With Washer - M12 1.5x80

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:13460

Part#: 33176760337

In Stock

$ 11.99

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

$ 9.99 USD

Add to Wish List

Qty

$ 9.99 USD

Add to Wish List

Replace your differential mounting hardware during service to eliminate problems caused by rusted or stripped hardware.

Genuine BMW Engine & Trans Suspension Hex Nut With Plate 22316760944 ...

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:7561

Part#: 22316760944

In Stock

$ 2.99 USD

Add to Wish List

Qty

$ 2.99 USD

Add to Wish List

Genuine BMW Hex Nut With Plate - M8
This item fits the following BMW Chassis:
E30 M3,E36 M3,E34 M5,E39 M5,E60 M5,E63 M6,E46 M3,E82 1M Coupe,E85 Z4M,E30,E34,E36,E38,E39,E46,E63,E65,E82,E85 Z4,E86 Z4,E89 Z4,E90,E92,E93,F22,F30,F31,F32,F33,F34,F36,F80 M3,F82 M4,F83

Show More Show Less

Genuine BMW Output Shaft Seal - 33107505604

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:360861

Part#: 33107505604

In Stock

9% off MSRP $ 18.20

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

$ 16.50 USD

Add to Wish List

Qty

9% off MSRP

$ 18.20

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

$ 16.50 USD

Add to Wish List

**Will only fit E92's after a production date of 9/2007 Two seals are required per vehicle. 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.

Show More Show Less

Differential Input Shaft Seal - Priced Each

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:49335120

Part#: 33121213949

In Stock

$ 18.99 USD

Add to Wish List

Qty

$ 18.99 USD

Add to Wish List

Replaces cracked or hardened valve body seals

Shaft Seal - Differential (Axle Drive)

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:54852004

Part#: B46.610

In Stock

$ 14.99 USD

Add to Wish List

Qty

$ 14.99 USD

Add to Wish List

This OEM-quality replacement shaft seal from Elring is the perfect fix for keeping your gear oil where it belongs.

Genuine BMW O-ring - 33111214144

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:25199

Part#: 33111214144

In Stock

$ 8.99 USD

Add to Wish List

Qty

$ 8.99 USD

Add to Wish List

Genuine BMW O-Ring - D=90Mm/3Mm
This item fits the following BMW Chassis:
E30 M3,E36 M3,E34 M5,E60 M5,E63 M6,E46 M3,E82 1M Coupe,E85 Z4M,E30,E34,E36,E38,E46,E63,E82,E85 Z4,E86 Z4,E90,E92,E93,F06,F10,F12,F13,F80 M3,F82 M4,F83

Show More Show Less

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

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
2X Entries For Our G87 M2 Sweepstakes!

T#:43750219

Part#: 33107505604

In Stock

$ 10.00 USD

Add to Wish List

Qty

$ 10.00 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

Corteco Output Shaft Seal

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

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

Driveshaft Seal

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:362306

Part#: 31507609535

In Stock

12% off MSRP $ 18.20

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

$ 15.95 USD

Add to Wish List

Qty

12% off MSRP

$ 18.20

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

$ 15.95 USD

Add to Wish List

Victor Reinz Differential Cover Gasket - E31, E32, E34, E39, E46, Z4 ...

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:362602

Part#: 33108305033

In Stock

$ 3.01 USD

Add to Wish List

Qty

$ 3.01 USD

Add to Wish List

Seals the rear differential cover

Driveshaft Seal

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

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

LSD Tune For OS Giken Differential

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:34382134

Part#: LSD-TUNE

Ships in 2 Business Days

$ 150.00 USD

Add to Wish List

Qty

$ 150.00 USD

Add to Wish List

Genuine BMW Differential Dust Cover

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:174741

Part#: 33137600693

Ships in 2 Business Days

$ 16.99 USD

Add to Wish List

Qty

$ 16.99 USD

Add to Wish List

Genuine BMW Dustcover Plate.

Output Shaft Seal

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:54744784

Part#: 24207588763

Ships in 1-2 days

$ 2.99 USD

Add to Wish List

Qty

$ 2.99 USD

Add to Wish List

If you notice a puddle of transmission fluid forming underneath your vehicle, the output shaft seal may have failed and is leaking. Stop the leak before it can cause internal transmission damage and replace the output shaft seal in your vehicle today. This seal is on the back of your transmission for the front to rear propeller or driveshaft.

Show More Show Less

E46, Z4 Differential Upgrade - 3.64 Original BMW

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:107

Part#: 33107514198

Ships in 8 Business Days

$ 2,680.99 USD

Add to Wish List

Qty

$ 2,680.99 USD

Add to Wish List

Price includes $100.00 core charge.

Differential Service Kit - With Service Tools

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:1002353

Part#: E46M3DIFSER1KT

Ships on Jul 28, 2026

$ 277.99

This product was last offered at the strikethrough price on
06-03-2026

$ 264.99 USD

Add to Wish List

Qty

$ 264.99 USD

Add to Wish List

Elring Differential Input Shaft Seal - 50x80x9mm - BMW E82 1M, E46 M3...

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:44733256

Part#: 703.190

Special Order: No Guaranteed ETA

$ 34.99 USD

Add to Wish List

Qty

$ 34.99 USD

Add to Wish List

If your differential is leaking fluid from the input shaft at the front of the diff case, there is a good chance this seal is faulty. Replace your leaking seal with this new seal from Elring to prevent further fluid loss and prevent damage to your differential. Replaces BMW p/n 33121213949, 33121212197, & 33121204847

Show More Show Less

Front Differential Bushing - Priced Each

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
We Price Match - Give Us A Call or Chat!

T#:36032352

Part#: 33176770788

Special Order: No Guaranteed ETA

$ 15.99 USD

Add to Wish List

Qty

$ 15.99 USD

Add to Wish List

The subframe serves as the mounting point for your rear suspension, connecting to the vehicle's body with bushings designed to absorb vibrations. These bushings minimize vibrations transmitted to the cabin while maintaining a secure and stable connection, ensuring tight and reliable suspension performance.

Show More Show Less

OEM Febi Rear Differential Carrier Bushing - Rear Positiom - E82/88 E...

Rear Position

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
We Price Match - Give Us A Call or Chat!

T#:382585

Part#: 33176770866

Special Order: No Guaranteed ETA

$ 47.99 USD

Add to Wish List

Qty

$ 47.99 USD

Add to Wish List

1
2

Select Vehicle

Purpose

Category

Differential and Gearing Upgrades

Brand

View All Brands

Price

Special Offers

Shipping