ACC PERFORMANCE 4749E Torque Converter Extension Gm Iv Ls 678118474930 Iii/iv

( Brand: Acc Performance ), ( Manufacturer Part Number: 4749E ), ( Part Type: Torque Converter ), ( Country Of Origin: Usa ), ( UPC: 678118474930 )

Review ACC PERFORMANCE Torque Converter Extension Gm Gen Iii/iv Ls fits PILOT

The **ACC Performance 4749E Torque Converter Pilot Extension** is a precision-engineered aftermarket component designed specifically for General Motors Gen III and Gen IV LS-series engines, offering a seamless upgrade to enhance drivetrain performance and responsiveness. This high-quality pilot extension is meticulously crafted to replace the stock pilot bearing assembly, which serves as the critical interface between the torque converter and the flexplate, ensuring smooth engagement and optimal torque transfer. Built from durable, heat-treated steel, the 4749E features a robust, oversized pilot bearing that reduces wear and friction, allowing for quicker and more consistent converter engagement especially under heavy loads or during aggressive driving conditions. Its precise machining and polished surface minimize vibration and harshness, delivering a noticeably smoother launch and improved throttle response, which is particularly beneficial for high-performance applications, towing, or daily driving enthusiasts seeking a more engaging yet refined shift experience. Compatible with a wide range of torque converters, including those from brands like Mopar, Ford, and aftermarket manufacturers, this extension is a straightforward bolt-on solution that requires no modifications to the transmission or engine bay. Whether paired with a stock converter for a subtle refinement or a high-performance unit for maximum torque multiplication, the ACC Performance 4749E ensures reliability and performance consistency, making it an essential upgrade for those looking to optimize their LS drivetrain s feel and efficiency.

### **Pros and Cons of buying a ACC Performance 4749E Torque Converter Pilot Extension for GM Gen III/IV LS Engines**

1. **Improved Shift Quality** The pilot extension enhances the engagement of the torque converter clutch, leading to smoother and more precise upshifts, especially in high-performance applications.

2. **Better Clutch Engagement** The extended pilot helps reduce the "clunk" or hesitation during clutch engagement, improving overall drivability.

3. **Compatibility with High-Performance Applications** Designed for GM Gen III/IV LS engines (including LS1, LS2, LS3, LS6, etc.), it works well with forced induction builds, supercharged, or turbocharged setups where torque converter clutch engagement is critical.

4. **Durability** ACC Performance products are known for their quality construction, ensuring longevity under heavy loads.

5. **Easy Installation** The kit is straightforward to install, requiring only basic tools and minimal modifications to the existing torque converter.

6. **Cost-Effective Upgrade** Compared to a full torque converter replacement, this is a relatively inexpensive way to improve shift feel and clutch engagement.

7. **Works with Stock and Aftermarket Converters** Compatible with both OEM and aftermarket torque converters, making it a versatile solution.

1. **Limited Performance Gain** While it improves clutch engagement, it does not significantly increase torque converter efficiency or horsepower output. Expectations should remain realistic.

2. **Not a Cure for Poor Transmission Tuning** If the transmission is already poorly tuned or worn, this modification alone may not resolve shift issues.

3. **Potential for Increased Wear on Clutch Packs** Some users report slightly faster wear on the torque converter clutch pack due to more aggressive engagement.

4. **Requires Proper Installation** Improper installation (e.g., incorrect alignment or torque specs) could lead to binding or premature failure.

5. **Not a Universal Fix for All Shift Problems** If the issue stems from a failing transmission or solenoid problems, this will not address those underlying concerns.

6. **Minimal Impact on Downshifts** The pilot extension primarily affects upshifts and clutch engagement; downshifts may not see significant improvement.

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### **Conclusion**

The **ACC Performance 4749E Torque Converter Pilot Extension** is a worthwhile upgrade for GM Gen III/IV LS engine applications where smooth clutch engagement and shift quality are priorities. It is particularly beneficial for high-performance builds, supercharged/turbocharged setups, or those experiencing minor shift hesitation. However, it is not a panacea for transmission issues and should be considered part of a broader tuning and maintenance strategy.

If your primary concern is **reducing clunkiness during upshifts** or **improving clutch engagement**, this kit delivers noticeable benefits at a low cost. For those with **severe transmission problems**, however, additional diagnostics or a full transmission rebuild may be necessary.

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### **Recommendation**

- You have a **Gen III/IV LS engine** (LS1, LS2, LS3, LS6, etc.).

- You experience **minor shift clunking or hesitation** during upshifts.

- You are running a **high-performance or forced induction build** where smooth torque converter engagement is important.

- You want a **simple, cost-effective solution** before considering a full torque converter swap.

- Your transmission has **severe internal wear or solenoid failures**.

- You are looking for **significant horsepower gains** this modification does not improve power output.

- You prefer **minimal modifications** and are satisfied with stock shift quality.

- Pair this with **proper transmission tuning** (via a programmer like HP Tuners or a dyno session).

- Ensure the **torque converter is in good condition** before installing.

- Follow **installation instructions carefully** to avoid binding or misalignment.

For most high-performance LS applications, this is a **solid, low-risk upgrade** that can enhance drivability without major drawbacks.

Details:

American Express.

part #: 4749e price

• $17.96

specifications cranshafengin:

• for models: Pilot
• brand: Acc Performance
• mpn: 4749e
• part type: Torque Converter
• country of origin: Usa
• upc: 678118474930

returns cranshafengin:

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

payments cranshafengin:

• credit card: Visa
• wallet: Paypal
• other

general cranshafengin:

• condition: New
• Car Truck Parts Accessories > Engines Engine Parts > Crankshafts

shipping cranshafengin:

• cost: $15.99
• service: Standard
• type: Fixed
• transit: 15-23 Days
• class: Standard

offer cranshafengin:

• quantity: 6
• started: June 9, 2026
• sold: 0
• options: Ship-to-home
• availability: In Stock

seller cranshafengin:

• # reviews: 634458
• city: , Ohio
• rating: 99.5%