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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.

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Premium Differential Service Kit - E46 M3, E9X M3, E82 1 M Coupe ...
Includes BMW SAF-XJ limited slip differential fluid with FM booster
Packaged by Turner - Corporate Logo
T#:598688
Part#: E46M3DIFSERTMSKT
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$ 277.83 USD
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Servicing your differential is an important job and should only be completed using high quality components! To ensure our customers are getting exactly what they need, we have put together this limited-slip differential service kit that includes all new fluid from BMW, a new BMW drain plug, and one of our new Titanium Magnetic Differential Drain Plugs!
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T#:42133544
Part#: 835225790TKT
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08-04-2026

$ 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
Packaged by Turner - Corporate Logo
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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$ 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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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

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$ 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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Packaged by Turner - Corporate Logo
T#:556968
Part#: 33112282482KT3
Ships on Aug 28, 2026
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$ 627.61 USD
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This kit includes Turner Motorsport solid aluminum differential race mounts pre installed in the differential cover for a quick install. These mounts where developed by Turner Motorsport for their Grand-Am Cup E46 M3 race cars, the advantages of solid aluminum mounts is increased suspension & drivetrain response, less drivetrain loss resulting in more wheel horsepower, and longevity - they effectively last forever. These CNC-machined mounts are a direct replacement for the stock rubber pieces, and have been lightened to remove excess weight. 

 

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Packaged by Turner - Corporate Logo
T#:56327180
Part#: F3XAWDFDKT5
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This product was last offered at the strikethrough price on
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$ 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

Packaged by Turner - Corporate Logo
T#:15744025
Part#: 331175250640-KT
In Stock
Sale - Save 8% $ 274.99

This product was last offered at the strikethrough price on
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$ 252.18 USD
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Sale - Save 8%
$ 274.99

This product was last offered at the strikethrough price on
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$ 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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T#:56038061
Part#: E9XSBFRDFFBKT2
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$ 491.99 USD
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This complete upgrade package is designed to put an end to steering slop. Utilizing a high performance 95A durometer polyurethane formulation, this kit replaces the mushy OEM rubber with proven rigidity.
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Packaged by Turner - Corporate Logo
T#:42099854
Part#: 07512293972T3KT
Ships in 1-2 days
Sale - Save 13% $ 303.99

This product was last offered at the strikethrough price on
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$ 264.15 USD
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Sale - Save 13%
$ 303.99

This product was last offered at the strikethrough price on
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$ 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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Packaged by Turner - Corporate Logo
T#:56327200
Part#: F3XAWDFDKT6
Ships in 2 Business Days
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$ 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
Packaged by Turner - Corporate Logo
T#:56471655
Part#: 27102413711KT3
Ships in 3 Business Days
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$ 228.99 USD
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This Transfer Case Repair Kit provides an exact-fit, OEM grade solution engineered to rebuild the servomotor assembly back to factory operating specifications. Designed for enthusiasts who demand crisp power transfer and exact mechanical feedback from their drivetrain.
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Packaged by Turner - Corporate Logo
T#:56471654
Part#: 27102413711KT2
Ships in 3 Business Days
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$ 228.99 USD
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This Transfer Case Repair Kit provides an exact-fit, OEM grade solution engineered to rebuild the servomotor assembly back to factory operating specifications. Designed for enthusiasts who demand crisp power transfer and exact mechanical feedback from their drivetrain.
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Packaged by Turner - Corporate Logo
T#:56616382
Part#: 27111226467KT3
Ships in 7 Business Days
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$ 48.99 USD
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This Transfer Case Service Kit replaces degraded fluid and sealing hardware to maintain proper lubrication within the all wheel drive transfer case. Unserviced transfer case fluid breaks down into sludge and deposits, causing lubrication loss and internal component wear; this service kit prevents internal wear by renewing fluid properties and drain hardware.
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Packaged by Turner - Corporate Logo
T#:56616376
Part#: 27111226467KT2
Ships in 7 Business Days
New Item
$ 48.99 USD
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This Transfer Case Service Kit replaces degraded fluid and sealing hardware to maintain proper lubrication within the all wheel drive transfer case. Unserviced transfer case fluid breaks down into sludge and deposits, causing lubrication loss and internal component wear; this service kit prevents internal wear by renewing fluid properties and drain hardware.
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Packaged by Turner - Corporate Logo
T#:56471658
Part#: 27102413711KT5
Ships in 3 Business Days
New Item
$ 228.99 USD
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This Transfer Case Repair Kit provides an exact-fit, OEM grade solution engineered to rebuild the servomotor assembly back to factory operating specifications. Designed for enthusiasts who demand crisp power transfer and exact mechanical feedback from their drivetrain.
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Packaged by Turner - Corporate Logo
T#:56471657
Part#: 27102413711KT4
Ships in 3 Business Days
New Item
$ 228.99 USD
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This Transfer Case Repair Kit provides an exact-fit, OEM grade solution engineered to rebuild the servomotor assembly back to factory operating specifications. Designed for enthusiasts who demand crisp power transfer and exact mechanical feedback from their drivetrain.
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Genuine BMW - Corporate Logo
T#:338092
Part#: 33107566176
Ships in 7 Business Days
Starting at $ 2,412.29 USD
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Starting at $ 2,412.29 USD
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This is a complete differential to change the gearing of a manual transmission E90/E92 325i, 328i, or 330i (not for xi models) to a 3.64 ratio final drive. The standard gearing on the manual transmission cars is 3.15 or 3.23, making this E90 diff significantly shorter. This diff is from a 330i automatic where the gear ratio has to be shorter to make up for the transmission gearing differences and extra weight. This will dramatically improve acceleration on any 325i, 328i or 330i INSTANTLY! If you are looking for better off-the-line or rolling acceleration, and are willing to sacrifice a little top-speed (some of us don't get up to 150mph), this is one of the best ways to achieve it with almost no downside. There are few things that can improve your 0-to-60 and 0-to-100 times as much as shorter gearing, and this differential is clearly a best "bang-for-buck" solution for dramatically better acceleration. Since this is an Original BMW part it carries the same BMW two year warranty as any other new part. So there's no need to take a chance on a used part from a private seller. (former BMW part number 33107519944)

Changing gear ratio changes the RPM range for any given speed. Use the chart below for examples of speed vs RPM changes for the 3.64 diff.
 

2006 330i, 6-speed manual, stock 3.15 gears, 255/35-18" rear tires

Gear RatioGearSpeedRPM

40 MPH in 4th

3.154th40 MPH2,100 RPM

3.644th40 MPH2,400 RPM

70 MPH Cruise

3.156th70 MPH2,500 RPM

3.646th70 MPH2,900 RPM

5th Gear Speed @ 6,000 RPM

3.155th142 MPH6,000 RPM

3.645th123 MPH6,000 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 E90 will top out at.2006-2011 325i or 328i, 6-speed manual, stock 3.23 gears, 255/35-18" rear tires

(click to expand)

Gear RatioGearSpeedRPM

40 MPH in 4th

3.234th40 MPH2,150 RPM

3.644th40 MPH2,400 RPM

70 MPH Cruise

3.236th70 MPH2,600 RPM

3.646th70 MPH2,900 RPM

5th Gear Speed @ 6,000 RPM

3.235th138 MPH6,000 RPM

3.645th123 MPH6,000 RPM

Speed in 5th gear at 6,000 RPM is for theoretical and comparison purposes only. It doesn't mean that these speeds are actually reachable.


A $100 refundable core charge must be added at the time of order. This core charge can be refunded when you ship your original diff back to us.

This item fits the following BMWs with manual transmission only:
2006-2011 E90 BMW 325i 328i 330i - Sedan
2006-2012 E91 BMW 325i 328i - Wagon
2007-2013 E92 BMW 328i - Coupe
2007-2013 E93 BMW 328i - Convertible

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Packaged by Turner - Corporate Logo
T#:55965861
Part#: 30309175WKWVTKT2
Ships on Aug 27, 2026
New Item
$ 1,269.99 USD
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This AutoTech LSD Upgrade Kit pairs AutoTech’s highly engineered 188mm limited-slip differential carrier with a pair of Corteco output shaft seals, giving you everything you need for a leak-free install.
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Febi - Corporate Logo
T#:56471642
Part#: 33316792873
Special Order: No Guaranteed ETA
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$ 12.99 USD
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The Febi Bilstein Rear Axle Differential Mount provides factory-spec structural retention to keep your differential firmly anchored.