fits make: Audi. year: 2005–2007.

( Manufacturer Part Number: 09L-300-037-KX ), ( Part Type: Tran Axle ), ( Year: 2005 2006 2007 ), ( Manufacturer Warranty: 1 Year ), ( Fitment Type: Direct Replacement ), ( Genuine Oem: Yes )
The **Audi 09L-300-037-KX Trans-Axle** is a high-performance, precision-engineered drivetrain component designed exclusively for Audi s front-wheel-drive (FWD) and all-wheel-drive (AWD) platforms, particularly those equipped with the 1.8T, 2.0T, and 2.8T engines spanning generations from the late 1990s through the early 2010s. This trans-axle serves as a critical link between the engine s power output and the front wheels, integrating the transmission and differential into a single, compact, and robust unit to optimize space efficiency and handling dynamics. Crafted from high-strength steel and reinforced alloys, the 09L-300-037-KX is built to withstand the demands of both daily driving and spirited performance, featuring a multi-plate wet clutch system for seamless gear engagement and a helical-bevel differential that ensures smooth power delivery while minimizing torque steer. The design incorporates Audi s signature **Quattro** all-wheel-drive capability in compatible models, allowing for dynamic torque distribution between the front and rear axles via a center differential, enhancing traction and stability across a variety of road conditions. This trans-axle is particularly notable for its integration with the **09L** transmission family, which includes variants like the 09L-300 (6-speed manual) and 09L-301 (6-speed automatic), ensuring compatibility with Audi s iconic models such as the A4, A6, TT, and S4, among others. Whether restored for a classic enthusiast or rebuilt for a high-mileage daily driver, the 09L-300-037-KX exemplifies Audi s commitment to blending German engineering precision with practical, performance-oriented drivetrain solutions. Its modular construction allows for straightforward maintenance, with accessible components like the oil pump, torque converter (in automatic variants), and differential gears, making it a favored choice for both professional mechanics and DIY automotive enthusiasts seeking reliability and longevity.
### **Pros and Cons of buying a Audi 09L-300-037-KX Trans-Axle**
The **Audi 09L-300-037-KX** is a trans-axle (transmission and axle combined) used in certain Audi models, particularly the **A4 B8 (2015 2023)** and **A5/C5 (2016 2023)** with the **09L 7-speed S tronic** transmission. Below is a detailed breakdown of its advantages and disadvantages.
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### **Pros**
1. **OEM Quality and Reliability**
- This is an **original Audi part**, meaning it meets the manufacturer s exact specifications for fit, function, and durability. Unlike aftermarket alternatives, it is designed to integrate seamlessly with the vehicle s drivetrain.
- Audi s engineering ensures proper synchronization with the **7-speed S tronic** transmission, reducing the risk of premature wear or compatibility issues.
2. **Long-Term Durability**
- Audi trans-axles are built to last **150,000 250,000 miles** under normal conditions, especially if the vehicle is maintained properly. The **09L-300-037-KX** is no exception, provided it is not subjected to severe abuse (e.g., aggressive driving, lack of fluid changes, or modifications).
- The **7-speed S tronic** is known for its robustness in Audi models, particularly when paired with the correct trans-axle.
3. **Warranty Coverage**
- If purchased **new from Audi or an authorized dealer**, this part may come with a **factory warranty** (typically 12 24 months or 12,000 24,000 miles, depending on the dealer).
- Some extended warranties or service plans may also cover it, adding peace of mind.
4. **Performance and Smooth Operation**
- The **09L trans-axle** is optimized for Audi s **TFSI (Turbo Fuel Stratified Injection) engines**, particularly the **2.0T and 2.9T** variants in the A4/A5. It provides **precise gear shifts** and **efficient power delivery**, which is crucial for handling and acceleration.
- The **integrated differential** ensures balanced power distribution, improving traction and drivability.
5. **Easier Maintenance (Compared to Separate Transmission Axle)**
- Since the trans-axle combines the transmission and axle into one unit, **fluid changes and inspections** can be done more efficiently than in a split system. This reduces labor time and potential for leaks or misalignment.
- Fewer moving parts in the drivetrain mean **less wear and tear** over time.
6. **Resale Value and Compatibility**
- Audi trans-axles remain in demand due to their **reliability and performance**, making them easier to sell or trade in if needed.
- The **09L-300-037-KX** is **directly compatible** with the following models:- **Audi A4 B8 (2015 2023)** with 2.0T or 2.9T engines
- **Audi A5/C5 (2016 2023)** with the same engine configurations
- It is also **interchangeable with some S5 and S6 models** (depending on the year and trim), expanding its usability.
7. **Superior to Aftermarket Alternatives**
- While aftermarket trans-axles (e.g., from **Megatech, ACDelco, or local shops**) may be cheaper, they often lack the **precision engineering, warranty support, and long-term reliability** of an OEM part.
- Cheap alternatives may also **void warranty coverage** on the transmission or drivetrain.
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### **Cons**
1. **High Upfront Cost**
- The **09L-300-037-KX trans-axle is expensive**, typically ranging from **$2,500 to $4,500 ** depending on the source (new vs. used, dealer vs. auction).
- This makes it a **significant investment**, especially if the vehicle already has transmission issues.
- **Labor costs** for installation (if not DIY) can add **$500 $1,500**, depending on the shop.
2. **Limited Availability and Lead Times**
- OEM parts, especially for **discontinued models**, can be **hard to find quickly**. Dealers may have long wait times (weeks to months) for stock.
- Purchasing from **third-party suppliers (e.g., RockAuto, eBay, or salvage yards)** may require verification of authenticity to avoid counterfeit parts.
3. **Potential for Hidden Issues in Used Units**
- If buying a **used/refurbished trans-axle**, there is a risk of **pre-existing damage** (e.g., worn synchronizers, leaking seals, or internal wear).
- Without a **full inspection or warranty**, you may end up paying for repairs shortly after installation.
- **Audi s warranty does not typically cover used parts**, so you are responsible for any failures.
4. **Complex Installation**
- Replacing a trans-axle is a **labor-intensive job** that requires:- Removing the engine/transmission assembly (in some cases, lifting the vehicle).
- Proper alignment of the **input/output shafts**.
- Torque specifications must be followed precisely to avoid damage.
- **DIY installation is difficult** for most owners due to the **specialized tools and expertise** required. Most will need a **mechanic with Audi experience**.
5. **Potential for Fluid Contamination**
- If the **old trans-axle was leaking or had degraded fluid**, residue can contaminate the **new unit**, leading to **premature wear**.
- A **full flush and filter replacement** is recommended before installation to prevent this.
6. **Weight and Space Constraints**
- The **09L trans-axle is heavy** (around **100 120 lbs**), which can make handling and installation more difficult.
- In some **tight engine bays (e.g., A5 Cabriolet)**, clearance may be an issue, requiring **modifications or careful removal of surrounding components**.
7. **Risk of Overuse or Misuse**
- If the vehicle has a history of **aggressive driving, towing, or lack of maintenance**, the trans-axle may not last as long as expected.
- **Ignoring transmission fluid changes** (every **60,000 100,000 miles**) can lead to **premature failure**, negating the benefits of a new unit.
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### **Conclusion**
The **Audi 09L-300-037-KX trans-axle** is a **high-quality, reliable component** that offers **superior performance, longevity, and compatibility** with Audi s **7-speed S tronic** systems. It is the **best choice for owners** who want **OEM reliability, warranty coverage, and long-term durability**, especially in **A4 B8 and A5/C5 models**.
However, the **high cost, installation complexity, and potential for hidden issues in used units** make it a **significant financial and logistical commitment**. It is **not the best option** for those on a tight budget or those who cannot afford professional installation.
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### **Recommendation**
#### **Buy the 09L-300-037-KX If:**You **own an A4 B8 or A5/C5 (2015 2023) with transmission issues** and want a **long-term, reliable fix**.
You **have the budget** ($3,000 $5,000 ) and can afford **professional installation** ( $1,000 $1,500).
You **prioritize OEM quality** over cost savings and want **warranty coverage**.
You **plan to keep the vehicle long-term** (100,000 miles) and maintain it properly (fluid changes, inspections).
You **cannot find a suitable aftermarket alternative** with equivalent reliability.
#### **Consider Alternatives If:**You are **on a tight budget** explore **aftermarket trans-axles** (e.g., **Megatech, ACDelco**) or **used OEM units** (with inspection).
You **lack the skills or tools** for DIY installation ensure you have a **trusted Audi specialist** for labor.
The vehicle has **other major issues** (e.g., engine problems, frame damage) a trans-axle replacement alone may not be enough.
You **cannot verify the part s authenticity** purchase from **authorized Audi dealers or reputable suppliers** (e.g., **RockAuto, eBay verified sellers**).
You **do not plan to keep the car long-term** a trans-axle is a **big investment** that may not be justified for short-term ownership.
#### **Best Approach:**1. **Get a professional diagnosis** confirm
Shipping Carrier substitutions may be made at our determination in an attempt to reduce shipping cost the customer. Parts must be resalable and in the original packaging. Genuine Audi Trans-Axle 09L-300-037-KX: Parts: A4, S4. Product Genuine Audi Trans-Axle 09L-300-037-KX.
Without Quarto. Electrical parts are not returnable.