1. Automatic Transmissions Products
  2. sku: 24072219169758632
  3. INFINITI 310203YX2B

INFINITI 310203YX2B Trans Axle

fits model: Qx60. make: Infiniti. year: 2015–2017.

310203yx2b Infiniti Genuine Trans-axle

( Manufacturer Part Number: 310203YX2B ), ( Part Type: Tran Axle ), ( Year: 2015 2016 2017 ), ( Manufacturer Warranty: 1 Year ), ( Fitment Type: Direct Replacement ), ( Genuine Oem: Yes )

Review INFINITI Genuine Trans axle fits QX60 2015–2017

The **Infiniti 310203YX2B Trans-Axle** is a precision-engineered, high-performance drivetrain component designed exclusively for select Infiniti models, including certain iterations of the **Q45, G35, and M35** vehicles equipped with all-wheel-drive (AWD) systems. This trans-axle serves as the rear axle assembly, integrating seamlessly with the front transaxle to deliver balanced power distribution, enhanced traction, and superior handling dynamics. Crafted from durable, high-grade materials, including forged aluminum and reinforced steel components, the 310203YX2B is built to withstand the demands of both daily driving and spirited performance applications. Its compact yet robust design houses a **spiral-bevel gearset**, optimized for efficiency and reduced noise, while the integrated differential housing houses a **limited-slip differential (LSD)** mechanism, ensuring optimal torque transfer between the front and rear axles for improved stability on slippery or uneven surfaces. The trans-axle is engineered with **precision-machined bearings and seals**, minimizing friction and preventing fluid leakage, which is critical for maintaining longevity and reliability under varying driving conditions. Additionally, it incorporates **adjustable drive shafts and constant velocity (CV) joints**, allowing for smooth power delivery while accommodating suspension movement and wheel articulation. Whether installed in a high-performance roadster or a luxury sedan, this trans-axle plays a pivotal role in delivering the refined balance of power, responsiveness, and comfort that Infiniti vehicles are renowned for. For enthusiasts and mechanics seeking a direct-fit replacement or an upgrade for their AWD-equipped Infiniti, the 310203YX2B represents a critical component that ensures both performance integrity and long-term durability.

### **Pros and Cons of buying a Infiniti 3.1L Trans-Axle (Part Number: 310203YX2B)**

#### **Pros:**

1. **Compatibility and Reliability** The Infiniti 3.1L trans-axle (also known as the **J31** engine) is a well-established unit, commonly found in models like the **G35, G37, and QX56**. Its widespread use means that parts, labor, and diagnostic knowledge are readily available, reducing long-term repair costs.

2. **Proven Performance** The 3.1L engine is a robust inline-six, known for smooth operation, good fuel efficiency for its class, and adequate power output (around **275 300 hp** in tuned applications). It is also less prone to catastrophic failure compared to some turbocharged or high-performance engines.

3. **Durability** With proper maintenance (regular oil changes, timing belt replacement, and fluid flushes), the 3.1L engine can last **200,000 miles**, especially in applications like the **G37 coupe**, which often sees less severe driving conditions than high-performance models.

4. **Aftermarket Support** The engine benefits from a strong aftermarket presence, including performance upgrades (intake, exhaust, ECU tuning), reliability mods (oil cooler, upgraded water pump), and even full rebuild kits. This makes it easier to modify or restore if needed.

5. **Lower Cost of Ownership (Compared to Some Alternatives)** While not cheap, the 3.1L is generally more affordable to maintain than high-performance V8s or turbocharged engines. Parts like the **transmission (JF515EF or JF515E)** are also relatively common and reasonably priced.

6. **Classic/Collectible Appeal** The G35 and G37 are highly sought-after performance cars, and the 3.1L engine is a key part of their character. Owning one can be appealing for enthusiasts who value driving dynamics and classic Infiniti styling.

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#### **Cons:** 1. **Aging Design Flaws** The 3.1L engine has some known weaknesses:

- **Timing Belt & Water Pump Failure** The belt and water pump are critical and must be replaced at **105,000 miles** (or every 5 years). Neglecting this can lead to **valve damage or engine failure**.

- **Oil Leaks** Common issues include **valve cover gasket leaks, oil filter housing leaks, and rear main seal leaks**, which can be costly to fix if not addressed early.

- **Head Gasket & Cooling System Issues** Some units suffer from **head gasket failure** (especially if overheated) or **coolant leaks from the thermostat housing or radiator hoses**.

- **Transmission Wear** The **JF515EF** (5-speed automatic) can develop **slippage, rough shifting, or solenoid failures** over time, requiring a rebuild or replacement.

2. **High Maintenance Costs Over Time** While parts are available, labor-intensive repairs (e.g., **engine rebuild, transmission overhaul, or major cooling system work**) can be expensive, especially if done by specialty shops.

3. **Fuel Economy Limitations** The 3.1L is not the most efficient engine, especially in high-performance trims. Expect **around 18 22 MPG in the city and 25 30 MPG on the highway**, which is decent but not great for modern standards.

4. **Depreciation & Market Value** While the G35/G37 hold value well for enthusiasts, they are not as valuable as some luxury or high-performance brands. If you plan to sell later, resale value may not be as strong as a **BMW M3, Porsche 911, or even a Toyota Supra**.

5. **Rust & Body Issues** Many older Infinitis (especially in snowy or coastal regions) suffer from **frame rust, wheel well corrosion, and interior wear**. A thorough inspection is essential before purchase.

6. **Limited Modern Tech** Compared to newer Infiniti models, the G35/G37 lacks **modern driver aids (adaptive cruise, lane-keeping), advanced infotainment, or hybrid/electric options**, which may be dealbreakers for some buyers.

---

### **Conclusion:**

The **Infiniti 3.1L trans-axle (310203YX2B)** is a **solid, capable engine** that offers **reliability, performance, and aftermarket support** making it a great choice for enthusiasts who appreciate **driving dynamics, classic styling, and moddability**. However, it comes with **known weaknesses (timing belt, leaks, transmission issues)** that require **proactive maintenance** to avoid costly repairs.

If you are **mechanically inclined, willing to invest in upkeep, and don t mind some aging quirks**, this engine is an excellent powerplant. On the other hand, if you prefer **lower maintenance, modern tech, or better fuel efficiency**, you may want to consider alternatives like a **Toyota 2JZ, Nissan VR38DETT, or even a modern turbocharged engine**.

---

### **Recommendation:** - **Buy if:**

- You are an **enthusiast who enjoys working on cars** and can handle **regular maintenance (timing belt, oil changes, leaks)**.

- You want a **fun, rear-wheel-drive performance car** with **mod potential** (e.g., G35/G37).

- You find the **classic styling and driving feel** appealing over modern luxury.

- You plan to **keep the car long-term** and are okay with **higher upfront costs for reliability**.

- **Avoid if:**

- You want a **low-maintenance, plug-and-play** vehicle with minimal repairs.

- You prioritize **modern tech, fuel efficiency, or high resale value**.

- You **cannot afford** potential **transmission or engine repairs** (e.g., $2,000 $4,000 for a rebuild).

- You live in an area with **severe winters** (rust and corrosion risks increase).

**Final Verdict:** The **3.1L trans-axle is a fantastic engine for the right buyer** someone who values **performance, moddability, and a classic driving experience** but it demands **attention and budgeting for maintenance**. If you re prepared for that, it s a **great choice**; otherwise, consider alternatives like the **Toyota 2JZ or Nissan VR38DETT** for similar performance with slightly different trade-offs.

Details:

Genuine Infiniti Trans-Axle 310203YX2B: Parts: QX60. 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. Electrical parts are not returnable.

part #: 310203yx2b price

  • $7103.82

specifications autotransmissionsgo:

  • for models: Qx60
  • for makes: Infiniti
  • for years: 2015-2017
  • mpn: 310203yx2b
  • part type: Tran Axle
  • year: 2015 2016 2017
  • manufacturer warranty: 1 Year
  • fitment type: Direct Replacement
  • genuine oem: Yes

shipping autotransmissionsgo:

  • class: Freight
  • type: Fixed
  • cost: $236.00
  • service: Flat Rate Freight

payments autotransmissionsgo:

  • credit card: Discover
  • wallet: Google-pay
  • other

general autotransmissionsgo:

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

offer autotransmissionsgo:

  • availability: In Stock
  • started: June 4, 2026
  • options: Ship-to-home
  • sold: 0
  • quantity: 2

returns autotransmissionsgo:

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

seller autotransmissionsgo:

  • city: Macon, Georgia
  • # reviews: 111
  • rating: 100.0%
for models: qx60, for makes: infiniti, for years: 2015-2017, part type: tran axle, year: 2015 2016 2017, manufacturer warranty: 1 year, fitment type: direct replacement, genuine oem: yes,
manufacturer: infiniti, category: auto parts > car truck parts accessories > transmission drivetrain > automatic transmission, sku: 24072219169758632,
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  • New. Offer #1 priced at $7103.82 + $236.00 shipping estimate = $7339.82* total. Genuine Infiniti Parts.+$236.00 shipping

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