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BMW Differential and Gearing Upgrades for BMW 5 Series E34 (1987-1995)

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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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Turner Titanium Magnetic Differential Drain Plug - M22x1.5

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T#:593924

Part#: 027030TMS01

In Stock

Sale - Save 25% $ 87.99

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

$ 65.99 USD

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$ 87.99

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

$ 65.99 USD

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When both extreme-duty protection and saving every gram matters: the Turner Magnetic Differential Drain Plug.

ECS Magnetic Differential Oil Drain Plug - Most BMW & Mini Models...

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T#:366828

Part#: 009314ECS01A

In Stock

Sale - Save 35% $ 60.99

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

$ 39.64 USD

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Sale - Save 35%

$ 60.99

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

$ 39.64 USD

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You use a magnetic drain plug for your engine oil, right? Why not apply the same proactive thinking to the differential too? This is a direct replacement magnetic differential drain plug for your BMW. It will catch and retain fine and larger metal particles in your diff oil. If you're proactive in your diff oil servicing, you will catch a minor issue long before it becomes a headache. Diff drain plug includes one sealing o-ring. Direct replacement for Genuine BMW part number(s): 33117525064, 33110308370, 33110152626

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Powerflex Rear Diff Front Mount Bushing - Street - E34 5 Series / E32...

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T#:13793032

Part#: PFR5-631

Ships in 2 Business Days

$ 55.99 USD

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Differentials serve the key purpose of transmitting power from the driveshaft to the axles. Factory rubber bushings absorb some of this power to allow for cushy, comfortable acceleration, at the expense of performance. Many OEM differential bushings are fast-wearing and failure prone, resulting in driveline slop and thunks when shifting or going over bumps. Powerflex polyurethane differential bushings are firmer than OEM rubber bushings, eliminating associated driveline slop and allowing for the crisp application of power to the ground, resulting in better throttle response and control. Powerflex is the number one selling suspension bushing manufacturer in Europe. Their experience with polyurethane bushing material and state-of-the art manufacturing techniques allows them to produce premium performance bushings, made to exact-fit standards. Powerflex performance polyurethane bushings are built to last longer than OEM rubber bushings, while improving performance and allowing for a more engaging driving experience. Use of Powerflex Copper Grease PCG1 is recommended for ease of installation. Periodic reapplication is recommended to extend squeak-free service life of bushings. Powerflex Black Series bushings are the ultimate in track and race bushings. Need bushings for a car that's street-driven? Powerflex street bushings are an ideal alternative for street driven vehicles and those that see occasional autocross or track time. Powerflex is proud to offer a lifetime warranty to the original purchaser on all products.

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E46 M3, E9X M3, E34 M5, E39 M5, Z4 M OS Giken Super Lock Limited Slip...

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T#:1387

Part#: BM237-HA

Special Order: No Guaranteed ETA

$ 1,950.00 USD

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$ 1,950.00 USD

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The M Dynamic limited slip unit on the M3 is designed to be a pure street car differential. It's simply not up to the rigors of professional or amateur racing. The OS Giken Super Lock LSD is giant step up in from a stock M3 lsd unit. It's ready for the extreme conditions of racing, offers 100% progressive locking capability, and is able to do this while operating smoothly and quietly. It's use of advanced technologies that make it perfect for both street cars AND pro race cars... and everything in between. We're excited to be carrying the OS Giken LSD unit in our performance catalog, as we've been using them in our own Championship winning M3 race cars.

OS Giken incorporated revolutionary new ideas when developing the their own limited slip diff, utilizing their accumulated racing knowledge and experience and over 4 years of development. Their design uses an unprecedented number of friction plates (up to 28 total!) for better locking force, better engagement/disengagement, and less generated heat. The end result of their efforts is the OS Giken's OS Super Lock LSD which offers incredible durability and reliability on street and track driven BMWs. The use of highest quality materials, precise machining, forged gears and sound engineering makes this LSD durable and reliable enough for road racing performance (which we can personally vouch for!). This is such a great design, in that it can be used in any situation -- whether it's for a street car, or a 100% Professional race car. Zero break-in required. Super smooth and quiet engagement, and 100% progressive locking capability. Professional installation is recommended.

This Limited Slip Differential Unit fits the following BMWs:
2001-2006 E46 M3 coupe & convertible
2008-2013 E9X M3 coupe & convertible
1991-1995 E34 M5 sedan
1999-2003 E39 M5 sedan
2006-2008 E85 Z4M Z4 M Coupe, Z4 M Roadster

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Powerflex Rear Diff Front Mount Bushing - Race - E34 5 Series - E32 7...

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T#:13793033

Part#: PFR5-631B

Ships in 2 Business Days

$ 61.99 USD

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The Powerflex Rear Diff Front Mount Bushing (Race) for BMW E34 5 Series and E32 7 Series is a premium upgrade designed for enhanced drivetrain stability and performance. Here’s another description:

Race-Grade Polyurethane: Part of Powerflex’s Race Series, this bushing is crafted from a super-stiff polyurethane compound, designed to eliminate the excessive movement found in factory rubber bushings. The Race Series is optimized for track and high-performance driving, where minimizing flex is crucial for precision handling.
Purpose: This bushing replaces the front mount of the rear differential, a critical point where unwanted flex can reduce performance. By stiffening this mount, the bushing ensures improved power transfer to the wheels and reduces drivetrain slop, making the car feel more connected and responsive.
Key Features:
- High Durability: Polyurethane in the Race Series is resistant to wear, oil, and contaminants, offering longevity far superior to rubber bushings, especially in harsh driving conditions.
- Maximized Control: The stiffer material prevents the differential from moving excessively under load, providing more consistent traction and improved rear-end stability.
- Straightforward Installation: This bushing is a direct replacement for the stock component, making it easy to fit and offering immediate performance benefits without extensive modifications.
Benefits:
1. Enhanced Power Delivery: By limiting differential movement, the car experiences less drivetrain lash and more precise power delivery, which is especially noticeable during hard acceleration and cornering.
2. Reduced Differential Flex: The reduction in flex at the diff mount allows for improved handling and cornering response, making the car more predictable and stable at higher speeds.
3. Track and Performance Ready: The Race Series bushing is designed for drivers who demand the best from their vehicles, especially in motorsport settings where precision and durability are key.
Fitment: Tailored specifically for the BMW E34 (5 Series) and E32 (7 Series) models, this bushing replaces the front differential mount and offers a perfect fit, ensuring no compromises on installation or function.

In summary, the Powerflex Rear Diff Front Mount Bushing (Race Series) is an essential upgrade for BMW E34 and E32 owners looking for improved drivetrain rigidity, better handling, and longer-lasting components. Perfect for performance enthusiasts and track-goers, it enhances rear suspension control and reduces drivetrain movement for sharper, more precise driving experiences.

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BMW S38 Helical Limited Slip Differential

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T#:379403

Part#: MF-TRS-05E39

Back Ordered

$ 999.99 USD

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$ 999.99 USD

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Allows for traction at all times by providing the most power to the wheel with more grip. Unlike plate differentials (1,1.5,2-way) helical LSDs can supply different spin rates to each axle, like when cornering.

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PowerFlex Heritage Rear Differential Bushing - Front Position - E34/E...

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T#:38229087

Part#: PFR5-631H

Ships in 2 Business Days

$ 55.99 USD

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This Rear Diff Front Mount Bushing is perfect for BMW E34 and E32 owners looking to improve their vehicle’s rear suspension dynamics and drivetrain stability. It’s an ideal choice for enthusiasts who want better control and responsiveness without sacrificing too much ride comfort, offering a long-lasting, low-maintenance upgrade for daily driving or performance use.

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Differential And LSD Tune

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T#:34382136

Part#: BM237HAKT

Ships on Jul 17, 2026

$ 2,100.00 USD

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$ 2,100.00 USD

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Upgrade to a better performing LSD, includes tune.

LSD Tune For OS Giken Differential

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T#:34382134

Part#: LSD-TUNE

Special Order: No Guaranteed ETA

$ 150.00 USD

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$ 150.00 USD

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