BMW Drivetrain Parts for BMW 3 Series E46 (1999-2005)

This kit from Valeo is a simple way to easily convert your stock dual mass flywheel clutch system to a single mass system.

Dual mass flywheels allow for fluid-feeling clutch engagements and offer a more luxurious feel than single-mass flywheels. However, with these benefits come significant drawbacks. Why convert from a dual-mass flywheel to a single-mass flywheel?

Cost: Dual-mass flywheels are expensive, with the cost of replacement often times being double or triple than that of converting to a single-mass flywheel.
Serviceability: Single-mass flywheels can be resurfaced, eliminating the need to replace with the next clutch service. - something that is not recommended with dual-mass flywheels, as they contain a rubber section that is more failure-prone in high mileage application.
Simplicity: Single-mass flywheels lack the complexity of dual-mass flywheels, making them inherently more reliable. Dual-mass flywheels contain a rubber damper or hub that will, like all rubber components, wear out with time.
Pedal Feel: Many enthusiasts prefer to eliminate BMW's "Self Adjusting Clutch", which has been known to provide an unpredictable, inconsistent engagement point.
Driveability: Valeo's conversion kit has been designed to maintain nearly identical clutch and flywheel weight, ideal for keeping the clutch quiet and easy to drive.
Kit contents:

Single-mass flywheel
Non-Self Adjusting Clutch and pressure plate
Throw out bearing
Pressure plate bolts
Flywheel bolts
Clutch alignment tool

MAGNETIC FENDER COVER:

Protect your finish when working under the hood with a high quality Turner fender cover. Made from a synthetic leather layer with a goose flannelette backing for durability and protection. The Turner fender cover holds a tight grip to your fender or core support with four 9.5" magnets sewn into the top layer.

Features:

• Durable synthetic leather with the Turner logo
• Soft goose flannelette backing
• Four 9.5" integrated magnets

Dimensions:

•  Extra Long 20" x 47"

TELESCOPING LED MIRROR:

You are going to love this tool. This Schwaben telescoping lighted mirror can get you out of a jam when you need to look at something you can not see any other way. Use with or with out the mirror attached. Lighting can reflect on mirror to light at many angles. Great for finding missing parts beneath engine block or oil leaks.

Features:

• Handy pocket clip
• Pivoting quick attach mirror for perfect viewing at any angle.
• Extends up to 26 1/4" for hard to reach places.
• Collapsed length 6.5" without mirror attached, 9.5" with 
• High quality mirror provided a perfect reflection.
• Easy on and off. Turns on when extended and off when collapsed.
• 44,000 MCD brightness.
• Long life span up to 100,000 hours on LED bulb.
• Operates on 3 AG3/LR41 batteries 
• Includes batteries

TELESCOPING MAGNET:

This Schwaben telescoping magnet is a great addition to any tool box. Magnet is rated to pickup 3.5 lbs. Stainless steel shaft is 7" collapsed and 26" extended. Magnet is encased in a aluminum sleeve to help prevent side of magnet from sticking. Cushion grip rubber handle works great with dry or oily hands.

MAGNETIC PARTS TRAYS:

Stop losing nuts, blots, and screws. The Schwaben magnetic parts tray has a large 4-3/8 inch diameter stainless steel bowl with a rubber-coated magnetic base that won't mar painted surfaces.

Attach the tray to any ferrous metal on the vehicle, and toss in your steel fasteners as you remove them. The magnet holds them safely in place until you are ready to use them again. Works right side up or inverted for under-car repairs.

A simple, effective solution to a common problem.

WARNING: This product contains chemicals known to the state of California to cause cancer, birth defects, and/or reproductive harm. See above warning label as well as http://www.p65warnings.ca.gov for further information on Proposition 65 warnings.

The ZF S5D 320Z 5-speed transmission is known for its robust design, exceptional durability, and impressive power-handling capability. Unfortunately, as these transmissions age, shifter-related issues have become increasingly common. Problems such as difficulty selecting gears, a sticky shifter, or a decline in shift quality are often the result of worn detent springs, pins, and bushings. These components are essential for precise gear engagement and proper shifter centering, making their replacement a critical step in maintaining optimal performance.

Replacing detents requires specialized tools known as "drifts," which are notoriously hard to find. Fortunately, we've developed a complete Detent Tool Kit, featuring five precision-engineered drifts designed for exact fitment in the ZF transmission's detent bores. This toolset makes detent replacement straightforward and minimizes the risk of damage to internal transmission components.

Features

Complete Tool Kit: Includes five precision-machined drifts specifically designed for the ZF 5-speed transmission’s detent bores and caps. Hassle-Free Detent Replacement: Simplifies the process of removing and installing detents with professional-grade precision. Protects Your Investment: Reduces the risk of damaging internal transmission components during service. Durable Construction: Made from heavy-duty 1045 steel for exceptional strength and long-lasting reliability.

The ECS Tuning Center Support Bearing Brace is engineered to improve drivetrain performance and longevity. The factory center support bearing features internal an internal rubber bushing to reduce NVH (noise, vibration, and harshness) transmission to the cabin. Unfortunately, this material choice falls short when it comes to performance applications. Under extreme load conditions, this bushing is prone to flexing, resulting in driveshaft misalignment. To address the shortcomings of the factory rubber center support carrier design, ECS engineers developed a set of precision-fit, split polyurethane bushings that secure tightly around the existing driveshaft bearing. Constructed from 30A durometer polyurethane, this material eliminates bushing deflection while maintaining minimal noise, vibration, and harshness (NVH). By eliminating deflection, this innovative solution not only improves durability but also ensures a significantly longer service life than the OEM center support bearing—making it an excellent upgrade for aging BMW chassis.

The polyurethane bushings are surrounded by a robust 6061-T6 billet aluminum bracket designed with strength and reliability in-mind. This bracket features a split design for hassle-free installation, eliminating the need to remove the driveshaft assembly entirely. To install the ECS Center Support Carrier, simply cut around your existing bearing, remove the factory brace, and clamp on your new bushings and bracket. This user-friendly approach saves time and simplifies maintenance or upgrades. Two stainless steel socket head screws are used to fasten the two-piece bracket, offering corrosion resistance and secure clamping under high torque and stress. This combination of materials and design ensures dependable performance and long-lasting durability, even in demanding applications.

Features & Benefits:

Performance-Designed Bushing Upgrade: 30A durometer polyurethane is used to eliminate bushing deflection while maintaining a smooth, quiet ride. Improved Longevity: Polyurethane construction offers a longer lifespan than factory rubber, ideal for enthusiasts looking to eliminate future CSB-related problems. Billet Aluminum Bracket: The upgraded bushings are encased in a 6061-T6 billet aluminum bracket for enhanced durability and improved performance. Easy Installation: Both the bushings and the bracket feature a two-piece split design, allowing for seamless installation without driveshaft removal. Reduce Deflection, Increase Rigidity: Designed with performance in mind, this upgrade eliminates excessive driveshaft movement for improved alignment and efficiency. Kit Includes:

ECS Driveshaft Center Support Bushings ECS Driveshaft Center Support Carrier (2) Stainless Steel Hex Head Screws (2) Flange Nuts (26117574872) Medium Strength Threadlocker (0.5ml) Installation Instructions:

ECS has provided a detailed, start-to-finish installation guide to aid in the process of installing your new Driveshaft Center Support Carrier.

Ensure your clutch system can get the all of the power to the wheels. Stock clutch components lack the ability to transmit the full torque and horsepower loads to the wheels without suffering from increased wear and eventual clutch fade. Sachs Performance Clutch Kits are designed for sport and race applications, delivering higher torque transmission without succumbing to wear and tear and fading over extended periods of abuse.

Sachs Performance Clutch Kits include the following upgraded components:

• Performance Pressure Plate - Increased clamping force and resistant to wear

• Performance Clutch Disc - Allows for higher clamping force, higher torque transmission, and better clutch engagement at higher RPM’s

• Performance Throwout Bearing - Designed for increased spring pressure and higher RPM function

These kits are available with two different clutch discs, Organic and Metallic. Organic clutch discs are perfect for both performance street and light-moderate track applications. Metallic are designed for specifically for full-time track use such as endurance racing, clubsport, autocross, hill climbing and 1/4 mile racing. Please be sure you are purchasing the kit that best fits your needs. Our sales staff can help with any questions or concerns you may have!

Sachs Performance is the racing and performance oriented selection of high quality parts from Sachs and ZF Engineering. Supplying countless brands with OE parts and offering one of the widest selection of OEM replacement parts, they are known for their exceptionally high quality products. You can purchase these performance parts with confidence, knowing they will resist heavy wear and tear for much longer than most other aftermarket options.

Ensure your clutch system can get the all of the power to the wheels. Stock clutch components lack the ability to transmit the full torque and horsepower loads to the wheels without suffering from increased wear and eventual clutch fade. Sachs Performance Clutch Kits are designed for sport and race applications, delivering higher torque transmission without succumbing to wear and tear and fading over extended periods of abuse.

Sachs Performance Clutch Kits include the following upgraded components:

• Performance Pressure Plate - Increased clamping force and resistant to wear

• Performance Clutch Disc - Allows for higher clamping force, higher torque transmission, and better clutch engagement at higher RPM’s

• Performance Throwout Bearing - Designed for increased spring pressure and higher RPM function

These kits are available with two different clutch discs, Organic and Metallic. Organic clutch discs are perfect for both performance street and light-moderate track applications. Metallic are designed for specifically for full-time track use such as endurance racing, clubsport, autocross, hill climbing and 1/4 mile racing. Please be sure you are purchasing the kit that best fits your needs. Our sales staff can help with any questions or concerns you may have!

Sachs Performance is the racing and performance oriented selection of high quality parts from Sachs and ZF Engineering. Supplying countless brands with OE parts and offering one of the widest selection of OEM replacement parts, they are known for their exceptionally high quality products. You can purchase these performance parts with confidence, knowing they will resist heavy wear and tear for much longer than most other aftermarket options.

Lightweight flywheel and upgraded clutch kit for improved throttle response, acceleration, and clutch feel - the perfect setup for daily-driven vehicles with up to 400 Ft/lbs of torque.

This performance clutch and flywheel kit utilizes an upgraded ECS E34 M5 clutch kit with their in-house engineered flywheel to fit all M5x and S5x motors with a 5-speed transmission. By eliminating the dual-mass flywheel and replacing it with a single-mass you are able to eliminate the slack and extra weight of the flywheel for a quicker throttle response and acceleration. Their upgraded clutch kit utilizes all the best features of the original M5 clutch with an upgraded pressure plate and clutch disc, with the new clutch you have a better, more engaged clutch pedal feel, engagement, and longevity.

Whether you're replacing a worn-out clutch or upgrading for increased power handling, this E34 M5 clutch and flywheel kit offers a reliable solution for enhanced pedal feel, power capacity, and overall driving satisfaction.

Paired with a modified geometry flywheel, the E34 M5 style clutch is ideally suited for most E36, E46, and others using the same powertrain. It checks all the boxes for essential clutch replacement features. While some aftermarket options may address slipping issues and worn-out clutches, they often sacrifice pedal feel, providing little to no resistance. A soft clutch not only kills the driving experience of your BMW but also reduces confidence when pushing the car to its limits.

On the contrary, you might be in the market for an upgraded clutch to handle your modified engine/forced induction builds. You go from an OE or aftermarket clutch option that has a lackluster and soft pedal feel to the complete opposite side of the spectrum, a very stiff clutch that grabs like an on-and-off switch making the clutch a pain almost undrivable on the street resulting in your favorite car turning into your least favorite car to drive.

The E34 M5 clutch and flywheel kit balances performance with practicality, ensuring a satisfying driving experience whether you're maintaining your BMW or preparing it for increased power demands.

Kit Contents:

Single Mass Flywheel - E34 M5 Clutch Geometry
Performance Clutch Disc and Pressure plate
Throw-out Bearing
Pilot Bearing
Clutch Alignment Tool
Flywheel Bolts - Qty 8
Pressure Plate Botls - Qty 6
Clutch features:

Torque Capacity (Crankshaft):
400 Ft / Lbs
Clutch Disc:
240mm Full face, performance organic friction material with integrated copper for enhanced heat dissipation and a long component life
OE-like friction backing plate design for smooth engagement with dual-stage damping springs to reduce gear noise and driveline chatter, and for smooth engagement
Pressure Plate
Increased clamp force over OEM, rated at 1,729lbs of pressure
Flywheel features:

Eliminates factory dual mass
Improved throttle response
Improved acceleration
Hardened 4140 Chromoly Steel
Designed for use with any E34 M5 pressure plate and clutch for OE-type clutch feel
Weighs in at just 16.5lbs vs Factory Dual Mass - 25.3 lbs
SFI certified
Fitment:
1992-1999 E36 BMW 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1999-2002 E46 BMW 323i 323ci 325i 325ci 328i 328ci 330i 330ci (5-speed)
1997-2002 Z3 BMW Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0i M Roadster M Coupe
2003-2005 E85 BMW Z4 2.5i Z4 3.0i (5-speed)

Pair with T#363031 or any flywheel designed to be used with the E34 M5 clutch.

Upgraded clutch kit to be used with E34 M5 architecture flywheels. Designed for factory and upgraded street car applications to handle up to 375 Ft/lbs at the crank.

Whether you're replacing a worn-out clutch or upgrading for increased power handling, this E34 M5 clutch kit offers a reliable solution for enhanced pedal feel, power capacity, and overall driving satisfaction.

Paired with a modified geometry flywheel, the E34 M5 style clutch is ideally suited for most E36, E46, and others using the same powertrain. It checks all the boxes for essential clutch replacement features. While some aftermarket options may address slipping issues and worn-out clutches, they often sacrifice pedal feel, providing little to no resistance. A soft clutch not only kills the driving experience of your BMW but also reduces confidence when pushing the car to its limits.

On the contrary, you might be in the market for an upgraded clutch to handle your modified engine/forced induction builds. You go from an OE or aftermarket clutch option that has a lackluster and soft pedal feel to the complete opposite side of the spectrum, a very stiff clutch that grabs like an on-and-off switch making the clutch a pain almost undrivable on the street resulting in your favorite car turning into your least favorite car to drive.

The E34 M5 clutch kit balances performance with practicality, ensuring a satisfying driving experience whether you're maintaining your BMW or preparing it for increased power demands.

Kit Contents:

Performance Clutch Disc and Pressure plate
Throw-out Bearing
Clutch Alignment Tool
Pilot Bearing
Clutch features:

Torque Capacity (Crankshaft):
375 Ft / Lbs
Clutch Disc:
240mm Full face, performance organic friction material with integrated copper for enhanced heat dissipation and a long component life
OE-like friction backing plate design for smooth engagement with dual-stage damping springs to reduce gear noise and driveline chatter, and for smooth engagement
Pressure Plate:
Increased clamp force over OEM, rated at 1,729lbs of pressure
Throw-out Bearing:
OE spec for ease of installation and reliable operation
Clutch Alignment Tool:
BMW small 10 spline design, made for perfect fitment into the crank bore
Perfect clutch disc spline and size, easy removal with pull tab
​Not all aftermarket clutch kits include this proper alignment tool! We ensured you received the proper tool for trouble-free installation!
Fitment:
1992-1999 E36 BMW 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1999-2002 E46 BMW 323i 323ci 325i 325ci 328i 328ci 330i 330ci (5-speed)
1997-2002 Z3 BMW Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0i M Roadster M Coupe
2003-2005 E85 BMW Z4 2.5i Z4 3.0i (5-speed)
1977-1989 E24 BMW M6
1982-1988 E28 BMW M5
1987-1995 E34 BMW M5

ECS Performance Clutch and Flywheel Kit – Built for Precision and Power

Step up your BMW’s driving experience with the ECS Performance Clutch and Flywheel Kit, engineered for drivers who demand improved throttle response, stronger engagement, and seamless power delivery. Featuring a modified E34 M5 clutch setup paired with an expertly crafted single-mass flywheel, this kit is designed to enhance both the feel and performance of M5x and S5x engines with 5-speed transmissions.

The single-mass flywheel replaces the bulky, factory dual-mass version, significantly reducing rotational weight for quicker throttle response and sharper acceleration. This kit retains the robustness of the M5 clutch but ups the ante with a reinforced pressure plate and clutch disc, giving you not only increased power handling but also a highly responsive pedal feel for precision control.

Perfect for both clutch replacements and power upgrades, the ECS Performance Clutch and Flywheel Kit transforms your driving experience without sacrificing pedal feel or adding unwanted stiffness. Say goodbye to spongy or overly rigid aftermarket options—this setup strikes the balance that enthusiasts crave, giving you both reliability and satisfaction behind the wheel.

Kit Contents:

Single Mass Flywheel with E34 M5 Clutch Geometry Upgraded Clutch Disc and Pressure Plate Throw-out Bearing and Pilot Bearing Clutch Alignment Tool Flywheel and Pressure Plate Bolts Clutch Highlights:

Torque Capacity: 375 ft-lbs at the crank 240mm Performance Clutch Disc: Organic friction material with copper for heat dissipation and durability OE-Like Backing Plate: Provides smooth engagement and reduced driveline chatter Reinforced Pressure Plate: Holds 1,729 lbs of pressure for a firm, predictable pedal Flywheel Highlights:

Single-Mass Construction: Replaces the heavy factory dual-mass flywheel 4140 Chromoly Steel: Lightweight yet robust (16.5 lbs vs. factory 25.3 lbs) Enhanced Response and Acceleration SFI Certified Developed with Precision: Engineered and quality-tested by ECS Tuning in our Ohio facility, this kit reflects the best in performance engineering. Utilizing advanced tools like FARO laser scanning and 3D CAD modeling, we ensure precision fitment, durability, and consistent results for every driver.

Polyurethane Transmission Mount Set - Street Performance

Your transmission mounts are the backbone of your drivetrain. Stock rubber mounts often degrade quickly, leading to excess movement, mis-shifts, and, in some cases, even chassis damage. ECS Tuning’s Street Performance Polyurethane Transmission Mount Set offers an upgraded solution built for street and track performance alike.

Constructed from high-quality polyurethane and 304 stainless steel, these mounts are crafted to withstand the demands of high-torque and forced-induction setups, minimizing deflection and giving you more direct power delivery. With a 70A durometer rating, these mounts offer the best of both worlds—stiff enough to handle aggressive driving but still comfortable for daily commutes. For track-focused builds, we also offer a stiffer 80A version (sold separately).

Key Features:

Improved Stability: Reduced transmission movement for fewer mis-shifts and over-revs Polyurethane Construction: Stronger than rubber, with excellent oil and water resistance Engaging Driving Experience: A more connected feel without excessive vibration Dual Options: Choose Street (70A) or Race (80A) to match your driving style Durable Design: Mechanical interlock feature for high-stress applications Pair your new clutch and flywheel kit with these premium mounts for an unparalleled driving experience. Plus, our DIY guide makes installation easy—ECS Tuning has you covered from start to finish!

Upgrade the whole driving experience of your car with a single mass clutch and flywheel conversation paired with new upgraded engine and transmission mounts. These street durometer mounts are 70 and 75 durometer for an improved but not too harsh driving experience. This clutch and flywheel upgrade features a slightly heavier pedal feel with smooth engagement, paired with your upgraded drivetrain mounts you are sure to have confidence in how sturdy your car drives!

Our performance clutch and flywheel kit utilizes an upgraded ECS E34 M5 clutch kit with our in-house engineered flywheel to fit all M5x and S5x motors with a 5-speed transmission. By eliminating the dual-mass flywheel and replacing it with a single-mass we are able to eliminate the slack and extra weight of the flywheel for a quicker throttle response and acceleration. Our upgraded clutch kit utilizes all the best features of the original M5 clutch with an upgraded pressure plate and clutch disc, with the new clutch you have a better, more engaged clutch pedal feel, engagement, and longevity.

Whether you're replacing a worn-out clutch or upgrading for increased power handling, this E34 M5 clutch and flywheel kit offers a reliable solution for enhanced pedal feel, power capacity, and overall driving satisfaction.

Paired with a modified geometry flywheel, the E34 M5 style clutch is ideally suited for most E36, E46, and others using the same powertrain. It checks all the boxes for essential clutch replacement features. While some aftermarket options may address slipping issues and worn-out clutches, they often sacrifice pedal feel, providing little to no resistance. A soft clutch not only kills the driving experience of your BMW but also reduces confidence when pushing the car to its limits.

On the contrary, you might be in the market for an upgraded clutch to handle your modified engine/forced induction builds. You go from an OE or aftermarket clutch option that has a lackluster and soft pedal feel to the complete opposite side of the spectrum, a very stiff clutch that grabs like an on-and-off switch making the clutch a pain almost undrivable on the street resulting in your favorite car turning into your least favorite car to drive.

The E34 M5 clutch and flywheel kit balances performance with practicality, ensuring a satisfying driving experience whether you're maintaining your BMW or preparing it for increased power demands.

Kit Contents:

Single Mass Flywheel - E34 M5 Clutch Geometry Performance Clutch Disc and Pressure plate Throw-out Bearing Pilot Bearing Clutch Alignment Tool Flywheel Bolts - Qty 8 Pressure Plate Botls - Qty 6 Clutch features:

Torque Capacity (Crankshaft): 375 Ft / Lbs Clutch Disc: 240mm Full face, performance organic friction material with integrated copper for enhanced heat dissipation and a long component life OE-like friction backing plate design for smooth engagement with dual-stage damping springs to reduce gear noise and driveline chatter, and for smooth engagement Pressure Plate Increased clamp force over OEM, rated at 1,729lbs of pressure Flywheel features:

Eliminates factory dual mass Improved throttle response Improved acceleration Hardened 4140 Chromoly Steel Designed for use with any E34 M5 pressure plate and clutch for OE-type clutch feel Weighs in at just 16.5lbs vs Factory Dual Mass - 25.3 lbs SFI certified Polyurethane Transmission Mount Set - Street

70A durometer rating - slightly stiffer than stock for improved shifting quality and driveline performance. Constructed of 304 stainless steel with bonded and constrained polyurethane. The transmission mounts in your car play a critical role in your suspension. With this in mind, the stock mounts have been known to experience failures causing over-revving, mis-shifts, and in extreme cases, even chassis damage. Combat this issue with upgraded polyurethane transmission mounts from ECS Tuning. Designed with the street and track in mind, we've got you covered no matter your driving style. Fears of torn mounts are a thing of the past; a mechanical interlock feature makes these mounts ideal even for high-torque, forced-induction applications. Engine Mounts - 75A Durometer

Keep your engine securely mounted with our solid, non-fluid-filled mounts. Our ECS 75A Durometer engine mounts are custom-made in-house by our leading R&D department. These mounts result from countless hours of research and testing to establish the best possible bushing design to minimize engine vibration and driveline deflection while maximizing strength. ECS Tuning's primary goal was to achieve an economical, durable & compliant ride while maximizing performance. After putting down thousands of real-world test miles on multiple vehicles, we've done just that. With exposure to heat and elements, your motor mounts will break down with increasing age. A secure mount* is vital to reduce drivetrain vibration and transfer as much horsepower to the wheels as possible. These mounts are an upgrade for non-M E36/E46 owners seeking a stiffer mount without sacrificing comfort and ride quality.

The Wavetrac® Torque Biasing Differential introduces an innovative solution for BMW enthusiasts. With its patented design, the Wavetrac® differential automatically enhances grip in low-traction conditions, setting it apart from conventional torque biasing differential designs.

Crafted with precision, the Wavetrac® differential features high-strength 9310 steel gears encased in case-hardened billet or forged steel bodies. ARP® fasteners are utilized throughout the differential, ensuring robustness and exceptional performance.

One of the defining features of the Wavetrac® differential is its maintenance-free design. Fresh from the factory, it's engineered to deliver a lifetime of service without the need for regular maintenance or rebuilds. To bolster the commitment to durability, all Wavetrac® differentials come with a transferable limited lifetime warranty.

For those seeking additional technical insights, comprehensive information on the Wavetrac® Differential can be found at this link: Wavetrac Technical Information.

It's important to note that the Wavetrac® differential is compatible with gear ratios of 3.15 and higher.

Important Note for Bolt Kits:

For vehicles equipped with a welded ring gear, the installation of this differential necessitates the removal, drilling, and installation of the welded ring gear from your stock differential. A Bolt Kit ES4368731 is an essential component for installing the ring gear onto the new differential. We strongly recommend consulting with a professional machine shop before purchasing this item and the necessary hardware kit. Please be aware that no technical drawings or instructions are provided, underscoring the importance of verifying compatibility and ensuring correct installation with your chosen machine shop.

It's crucial to be aware that no refunds or replacements will be offered if the differential has been installed or machined, or in the event of incorrect ring gear installation or differential failure due to improper installation.