• Complete hardware replacement kit
• Includes 10 Differential Ring Gear Bolts and new axle seals
• Ensures optimal performance for your differential
• Ideal for upgrading to a Limited-Slip differential or restoring your existing one
• Hassle-free installation process

Differential Rebuild Kit Plus by Team MFactory

Upgrade your BMW's differential with the Differential Rebuild Kit Plus by Team MFactory. Whether you've recently replaced your differential or upgraded to a Limited-Slip, it's essential to replace the hardware to ensure optimal performance. This comprehensive kit from ECS Tuning includes 10 Differential Ring Gear Bolts, new axle seals, and new differential bearings, providing everything you need for a complete differential rebuild. With high-quality components, you can trust this kit to support your new differential or rebuild your existing unit effectively.

• Comprehensive kit includes Differential Ring Gear Bolts, axle seals, and differential bearings
• Ensures optimal performance of your BMW's differential
• Perfect for differential replacement or upgrades to Limited-Slip
• High-quality components for reliability and durability
• Provides all necessary hardware for a complete rebuild

Hands down - one of the best performance upgrades you can make to an E46 M3, E60 M5 or E63/E64 M6! With almost no downside you can make your BMW much quicker by swapping in a new ring & pinion gear set. The gearing used to be overlooked when planning modifications but the 3.85, 3.91, and 4.10 gears are now one of our biggest selling upgrades for the E46 M3! With a rear end gear upgrade you get the effects of adding horsepower but without adding any more stress to the engine or drivetrain. It's one of the best areas to get return from your modification spending. Using a shorter (numerically higher) gear ratio will give you better acceleration. The R&P acts as a torque multiplier, putting the engine into the power band sooner for each gear. There is an 6% increase in torque at the wheels with the shorter R&P. Want to make your car faster off the line or out of corners? Or avoid a downshift to pass on the highway? This is what you need.

The R&P can be installed on its own but for cars that have more than 60,000 miles it would be a better idea to rebuild the whole diff. The factory viscous limited slip units have a typical lifespan of 50-70,000 miles. We offer diff rebuilding with 3.85 or other gear options and you get a fully-rebuilt and serviced limited slip unit at the same time. Click here for our diff rebuild options.

3.85 Gearing Example: 2004 M3, 6-speed manual, 275/35-19" rear tires

Gear RatioGearSpeedRPM

40 MPH in 4th
3.62 4th 40mph 2,250rpm
3.85 4th 40mph 2,350rpm

70 MPH Cruise
3.62 6th 70mph 2,650rpm
3.85 6th 70mph 2,800rpm

5th Gear Speed at Redline
3.62 5th 175mph 8,000rpm
3.85 5th 165mph 8,000rpm

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 M3 will top out at.

This item is the genuine BMW part and the ring & pinion set only. You will need to have this professionally installed into your existing differential. BMW does not supply differential rebuild parts (bearings, shims, plates, etc.) so only a qualified shop that is experienced in BMW diff rebuilding should perform this installation. We also offer built differentials and exchanges, click here.

This item fits the following BMWs:
2001-2006 E46 BMW M3
2004-2010 E60 BMW M5
2004-2011 E63 BMW M6

OEM part number 33108311351

When it comes to gaining a significant advantage over your competitors, the MFactory Helical Limited Slip Differential (LSD) is your ultimate ally. This LSD offers a seamless and consistent distribution of power to your vehicle's wheels, allowing you to harness maximum traction and put the power firmly on the ground.

But what does an LSD do, you ask? Well, without an LSD, your car essentially operates as a "1-wheel drive," as it can't deliver torque to both wheels simultaneously. Instead, it directs torque to the wheel with less grip, highlighting the limitations of an open differential, which is standard in most vehicles.

An LSD, on the other hand, permits the wheels to spin at slightly different speeds by a limited amount, typically represented as a percentage difference. It's when the differential locks that both wheels receive power. It's important to note that LSDs function differently from locked differentials, such as those in off-road trucks, which supply equal torque and rotational speed to both rear wheels simultaneously, often causing handling issues.

Key Features:

• Crafted from imported Japanese SAE 4320 Steel
• Industry-first 30-day "Feel the Torque™" money-back guarantee, along with a Limited-Lifetime Warranty
• Forged, double tempered, and super sub-zero treated for unparalleled toughness
• Utilizes advanced Shot Peening technology to increase surface hardness
• Engineered to withstand the extreme shock loads of competition-level drag racing
• Advanced gear geometry designed using industry-leading software, delivering more power to the ground
• Exclusively uses the highest quality Brighton-Best Hardware
• Maintenance-free gears eliminate the need for special fluids and rebuilds associated with plate-type LSDs
• Ensures lock-free operation, preventing adverse effects on steering response
• Rated for up to ~1000 WHp

As part of the break-in procedure, we recommend changing the fluid after the first 3-400 miles of use.

Warranty:

MFactory Competition Products stands behind the quality of its Helical LSDs. A limited lifetime warranty is provided, ensuring that these LSDs are free of defects in materials and workmanship upon receipt of the product and professional installation. Any part returned must be determined by MFactory Competition Products to be defective before any warranty credit or replacement is issued.

MFactory Competition Products's obligation under the warranty is limited to repairing or replacing, at its discretion, any part proven defective. The customer is responsible for prepaying transportation charges.

It's important to note that the final determination of the suitability of the products for the intended use is the sole responsibility of the buyer. MFactory Competition Products shall not be liable for any special, direct, indirect, incidental, or consequential damages, including claims for delay, loss of profits, or labor that might be claimed as a result of the failure of any part.

Furthermore, MFactory Competition Products shall not be liable for any damage or injury to persons or property resulting from improper installation or misuse of any part covered by this warranty.

Please be aware that there are no other warranties, whether expressed or implied, extending beyond those set forth above.

Note: To ensure a proper fit, you'll need to reuse the old bearings or acquire new bearings and press them onto each end.