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Differential and Gearing Upgrades

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.

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Rear Differential Service Kit for various BMW Models

T#:42133544

Part#: 835225790TKT

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Sale - Save 2% $ 60.99

This product was last offered at the strikethrough price on
08-04-2026

$ 59.72 USD

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$ 59.72 USD

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The kit includes 2 Quarts of Red line 75w90 - 57904 and brand new Rein rear diff oil drain plug M22x1.5

Differential Service Kit

T#:15710761

Part#: 33117525064-KT

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Sale - Save 2% $ 100.76

This product was last offered at the strikethrough price on
06-15-2026

$ 98.71 USD

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Sale - Save 2%

$ 100.76

This product was last offered at the strikethrough price on
06-15-2026

$ 98.71 USD

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Often overlooked, scheduled rear differential service is very important. Over time gear lube breaks down causing bearings and internal components fail. Regular maintenance will keep your vehicle running properly for years to come. Kit includes 3 Bottles of Castrol SAF-XJ 75w140 2 Drain plugs

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ECS & Turner Performance Drivetrain Bushing Package - E82/88 E9X N52 ...

T#:24344778

Part#: ECSTMSPDBKT

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Sale - Save 8% $ 1,190.99

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

$ 1,096.14 USD

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$ 1,190.99

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

$ 1,096.14 USD

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Turner recommends running drivetrain mounts of all the same variety - if you are using poly engine mounts, you should also use poly transmission mounts. This kit is your solution to make sure all components of your vehicle are working with each other to achieve the performance you're looking for. Polyurethane material is more resistant to water, ozone, and chemicals, maintaining its resiliency and elasticity longer than conventional rubber. Keep your vehicle planted for spirited driving while having crisper throttle response and reduce drivetrain movement along with wheel hop. Kit includes: Turner Engine Mount Set - 60A Polyurethane ECS Transmission Mount Set - Street 70A Polyurethane ECS Differential Bushing Set - 95A Polyurethane ECS Subframe Mount Set - 95A - Polyurethane

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Billet Diff Cover Replacement Drain Plug

T#:19362530

Part#: 4835K45

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Sale - Save 15% $ 6.99

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

$ 5.93 USD

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$ 6.99

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05-03-2026

$ 5.93 USD

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

Axle Bearing Seal - Priced Each

T#:26038535

Part#: 33113604119

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Sale - Save 39% $ 3.99

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

$ 2.44 USD

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$ 3.99

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

$ 2.44 USD

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Bremmen Parts Axle Bearing Seal - ID=81mm/2mm

This item fits the following BMW chassis:

E10 E21 E30 E36 E36/7 Z3

Front and Rear Differential Service Kit - F3x

T#:56327180

Part#: F3XAWDFDKT5

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Sale - Save 1% $ 104.99

This product was last offered at the strikethrough price on
08-04-2026

$ 103.54 USD

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$ 104.99

This product was last offered at the strikethrough price on
08-04-2026

$ 103.54 USD

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This kit combines Red Line 75W85 GL-5 Synthetic Gear Oil with Rein OEM replacement plugs in order to perform a full drain and fill service on both of your differentials

Differential Service Kit

T#:15744025

Part#: 331175250640-KT

In Stock

Sale - Save 8% $ 274.99

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

$ 252.18 USD

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Sale - Save 8%

$ 274.99

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

$ 252.18 USD

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Often overlooked, scheduled rear differential service is very important. Over time gear lube breaks down causing bearings and internal components fail. Regular maintenance will keep your vehicle running properly for years to come. Three bottle of Genuine BMW Limited Slip Gear Lube 1 New Genuine BMW Drain/Fill plugs 1 ECS Magnetic Differential Oil Drain Plug Drain plug O-ring

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Front and Rear Differential Service Kit - F3x

T#:56327200

Part#: F3XAWDFDKT6

Ships in 1 Business Day

$ 154.99

This product was last offered at the strikethrough price on
08-07-2026

$ 154.52 USD

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$ 154.52 USD

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This kit combines Motul 75W85 GL-5 Synthetic Gear Oil with Rein OEM replacement plugs in order to perform a full drain and fill service on both of your differentials

Complete Xdrive Differential And Transfer Case Service Kit - E90, E91...

T#:42099854

Part#: 07512293972T3KT

Ships in 1-3 days

Sale - Save 13% $ 303.99

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

$ 264.15 USD

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Sale - Save 13%

$ 303.99

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

$ 264.15 USD

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Maintain smooth power distribution, protect your drivetrain, and extend the life of your BMW xDrive system with the Complete Xdrive Differential And Transfer Case Service Kit - E90, E91, E92, E60, E61, E70.

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Differential and Gearing Upgrades

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