MERCEDES 78403 Automatic Transmission Benz

( Manufacturer Part Number: 78403 ), ( Manufacturer Warranty: 90 Day ), ( Genuine Oem: Yes ), ( Seller Notes: A, 3.5l, 04/08 ), ( Make: Mercedes-benz ), ( Interchange Item Code: 400 ), ( Color: Black ), ( Type: Automatic Transmission Assembly )

Review MERCEDES benz Used Automatic Transmission Assembly Ml class fits 2008

The **Mercedes-Benz 78403 Automatic Transmission (7G-Tronic) from the 2008 ML-Class** represents a pinnacle of engineering precision, meticulously designed to deliver seamless, responsive, and efficient power delivery in one of the most iconic luxury SUVs of its era. This transmission is the heart of the ML-Class s dynamic performance, seamlessly integrating with the vehicle s powerful inline-six or V8 engines to offer a driving experience that balances sophistication with raw capability. Engineered by Mercedes-Benz s advanced transmission specialists, the **7G-Tronic** is a six-speed automatic with a fully electronic shift control system, ensuring smooth gear changes even under the most demanding conditions whether navigating tight city streets, cruising on the highway, or tackling rugged off-road terrain. Its robust construction incorporates high-strength materials, including precision-machined gears and a reinforced torque converter, allowing it to handle the substantial power outputs of the ML-Class s engine lineup without compromising on durability or reliability. The transmission s hydraulic system is calibrated to optimize shifting dynamics, reducing lag and enhancing acceleration while minimizing wear, making it a standout feature in its class. Additionally, the **78403** incorporates Mercedes-Benz s signature **7G-Tronic** technology, which includes a **twin-clutch system** in some configurations, enabling ultra-fast shifts and a near-instantaneous response ideal for both spirited driving and the demands of towing or heavy loads. This transmission is also equipped with advanced diagnostics and self-adjusting features, ensuring optimal performance over the vehicle s lifespan. Whether paired with the naturally aspirated M275 inline-six or the high-performance M276 V8, the **78403** delivers a harmonious blend of power, refinement, and longevity, embodying the Mercedes-Benz ethos of uncompromising quality and driving pleasure.

### **Pros and Cons of Buying a 2008 Mercedes-Benz ML-Class (W164) with the 78403 Automatic Transmission**

#### **Pros**

1. **Strong Engine and Performance**

The 2008 ML-Class typically comes with a **5.5L V8 (M177) engine**, which produces around **388 400 horsepower** and **402 lb-ft of torque**. This provides solid acceleration and towing capability, making it suitable for both on-road driving and light off-roading (with the optional 4MATIC all-wheel drive).

2. **Comfortable and Spacious Interior**

The ML-Class is a mid-size luxury SUV with a **roomy cabin**, comfortable seating for five, and high-quality materials in higher trims (e.g., AMG, SEL, or 4MATIC). The **rear seats** are particularly spacious, and the **sunroof** (if equipped) adds to the premium feel.

3. **Reliable Automatic Transmission (78403)**

The **78403** is a **7-speed automatic transmission** (later models may have the **7G-Tronic**), known for smooth shifting and durability when properly maintained. Unlike some older Mercedes transmissions, this one is **not prone to major failures** if serviced regularly.

4. **Luxury and Comfort Features**

The ML-Class offers **heated/ventilated seats**, **power-adjustable pedals**, **premium audio systems** (Bose or Burmester), and **advanced climate control**. The **suspension is well-tuned** for a smooth ride, though it may feel slightly firm compared to newer models.

5. **Good Resale Value for a Used Luxury SUV**

Mercedes-Benz models retain their value relatively well, and the ML-Class (especially in lower trims) can still fetch a decent price in the used market if well-maintained.

6. **Optional 4MATIC All-Wheel Drive**

If equipped with **4MATIC**, the ML-Class handles **wet or snowy conditions** better than a rear-wheel-drive model, making it a practical choice for drivers in varied climates.

7. **Classic Mercedes-Benz Build Quality**

The **chassis and body structure** are sturdy, and the **interior components** (like the gear shifter, steering wheel, and infotainment system) are well-built, though some may find the **infotainment interface outdated** by modern standards.

---

#### **Cons**

1. **High Maintenance Costs**

Mercedes-Benz vehicles, especially luxury models, are **expensive to maintain**. Regular **oil changes, transmission fluid flushes, and potential electrical issues** (e.g., sensors, infotainment) can add up quickly. **Brake pads, rotors, and tires** are also costly replacements.

2. **Fuel Efficiency is Poor**

The **5.5L V8** gets around **12 14 MPG combined**, making it **one of the least efficient SUVs** in its class. Fuel costs will be significantly higher than a modern turbocharged or hybrid SUV.

3. **Outdated Technology and Infotainment**

The **navigation system, Bluetooth connectivity, and overall tech** are **severely outdated** compared to modern standards. The **screen size is small**, and **Apple CarPlay/Android Auto are not available**. Upgrading the infotainment system can be expensive.

4. **Potential Electrical and Sensor Issues**

Older Mercedes models (especially pre-2010) are known for **electrical gremlins**, including **faulty sensors, dashboard warning lights, and intermittent issues** with the **transmission or engine management systems**. A **comprehensive diagnostic check** is essential before purchase.

5. **Transmission Wear Over Time**

While the **78403 is generally reliable**, **7-speed automatics** in older Mercedes can develop **rough shifting, delayed engagement, or fluid-related issues** if not properly serviced. **Transmission fluid should be flushed every 60,000 100,000 miles** neglecting this can lead to costly repairs.

6. **Rust and Body Condition Concerns**

The **W164 ML-Class** has been known for **rust issues**, particularly in **wheel wells, rocker panels, and undercarriage**. A **pre-purchase inspection** should check for **corrosion**, as repairs can be extensive and expensive.

7. **Comfort vs. Off-Road Capability Trade-Off**

While the ML-Class has **some off-road features** (like **locking rear differential in higher trims**), it is **not a true off-roader**. The **suspension is tuned for comfort**, not rough terrain, so expect **limited capability** compared to dedicated SUVs like the Jeep Wrangler or Toyota 4Runner.

8. **Depreciation and Age-Related Wear**

The **2008 model is now over 15 years old**, meaning **wear on the engine, transmission, and suspension** may be more advanced. **Timing belt replacement (if applicable), water pump, and differential service** should be checked.

9. **Resale Value Decline**

While it retains value better than some luxury brands, the **ML-Class is not a high-demand used luxury SUV**. If you plan to sell later, you may not recover as much as you spent.

10. **Potential for Hidden Mechanical Issues**

Older Mercedes can develop **engine misfires, turbocharger problems (if equipped), or exhaust manifold cracks**. A **pre-purchase inspection by a Mercedes specialist** is **highly recommended** to avoid costly surprises.

---

### **Ending Conclusion**

The **2008 Mercedes-Benz ML-Class (W164) with the 78403 automatic transmission** is a **solid choice for buyers who prioritize luxury, space, and a powerful V8 engine** but only if they are prepared for **higher maintenance costs, poor fuel efficiency, and outdated technology**. It remains a **comfortable, capable SUV** for daily driving, light towing, and all-wheel-drive capability (if equipped), but it is **not ideal for fuel-conscious buyers or those seeking modern tech**.

If you **inspect it thoroughly, maintain it properly, and budget for potential repairs**, it can be a **rewarding purchase**. However, if you want **better fuel economy, modern infotainment, or off-road capability**, newer models (or alternative brands like **Lexus, BMW X5, or Audi Q5**) may be more suitable.

---

### **Recommendation**

You **need a spacious, comfortable luxury SUV** for family use.

You **plan to keep it long-term** and are willing to **budget for maintenance**.

You **drive mostly on paved roads** and don t need extreme off-road performance.

You **find a well-maintained example** with **full service records** and a **pre-purchase inspection**.

You **prioritize fuel efficiency** (look for a hybrid or turbocharged SUV).

You **want modern infotainment** (Apple CarPlay, Android Auto, large touchscreen).

You **plan to tow heavily** (consider a newer Mercedes or a truck-based SUV).

You **cannot afford potential repairs** (transmission, electrical, or engine issues).

This ML-Class is a **good used luxury SUV for the right buyer** one who values **comfort, power, and Mercedes-Benz prestige** over cutting-edge technology. **Always get a professional inspection** before purchasing to ensure it s in **sound mechanical condition**.

Details:

Parts go back into cars rather than landfill. Original parts mean a perfect fit. Every part is cleaned, tested and inspected by experts. Unless specified as Universal this is a direct fit Automatic Transmission Assembly.

164 Type AT ML350 722.906. All parts are covered by warranty. This part fits vehicles made in the following years 2006 ,2007, 2008 ,2009.

part #: 78403 prices

• $420.00-$1055.74

specifications autotransmissionsgo:

• for makes: Mercedes
• for years: 2008
• mpn: 78403
• manufacturer warranty: 90 Day
• genuine oem: Yes
• seller notes: A, 3.5l, 04/08
• make: Mercedes-benz
• interchange item code: 400
• color: Black
• type: Automatic Transmission Assembly

payments autotransmissionsgo:

• wallet: Apple-pay
• other
• credit card: Mastercard

seller autotransmissionsgo:

• city: Taneytown, Maryland
• rating: 100.0%
• # reviews: 250

shipping autotransmissionsgo:

• service: UPS Ground Saver, Flat Rate Freight
• carrier: UPS
• type: Fixed
• class: Economy, Freight
• transit: 9-13 Days
• cost: $0.00

returns autotransmissionsgo:

• time: 30 Days
• paid by: Buyer
• policy: Returns Accepted

general autotransmissionsgo:

• Car Truck Parts Accessories > Transmission Drivetrain > Automatic Transmission
• condition: Used

offer autotransmissionsgo:

• availability: In Stock
• quantity: 1
• started: April 25, 2026
• sold: 0
• options: Ship-to-home

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