TCI 399606 Flexplate Select Gm Transmission 099998984348

( Brand: Tci ), ( Manufacturer Part Number: 399606 ), ( Part Type: Transmission ), ( UPC: 099998984348 )

Review TCI Premium Series Flexplate Select Gm Transmissions External

The **TCI 399606 Flexplate for Select GM Transmissions** is a high-performance, precision-engineered component designed to deliver exceptional durability and smooth operation in a wide range of General Motors automatic transmissions, including those found in classic muscle cars, trucks, and modern performance applications. Crafted from premium-grade steel, this flexplate is built to withstand the demands of high torque loads, aggressive driving styles, and extended use without compromising structural integrity or performance. The robust construction ensures minimal flex and vibration, which translates to a quieter drivetrain, reduced wear on the torque converter, and improved overall transmission longevity. This flexplate is specifically engineered to fit select GM transmissions, such as those in the **TH350, TH400, 700R4, 4L60, 4L65, and 4L80** series, making it an ideal upgrade for enthusiasts seeking to enhance the reliability and responsiveness of their vehicle s power delivery system. Its compatibility extends beyond stock applications, allowing for seamless integration with aftermarket torque converters, flywheel adapters, and performance-oriented drivetrains. The precision machining and heat-treatment process ensure consistent weight distribution and optimal balance, reducing harshness and improving drivability. Whether used in a restored classic, a high-mileage workhorse, or a modern performance build, this flexplate serves as a critical link between the engine and transmission, ensuring efficient power transfer and a more refined driving experience. Built to meet or exceed OEM specifications, it is an excellent choice for both restoration projects and high-performance modifications, offering a balance of strength, precision, and reliability that sets it apart from generic or lower-quality alternatives.

### **Pros and Cons of Buying a TCI 399606 Flexplate for GM 6-Speed Automatic Transmissions**

1. **Compatibility with Multiple GM Vehicles** The TCI 399606 flexplate is designed to fit a wide range of GM 6-speed automatic transmissions, including those found in the **LS1, LS2, LS3, LT1, and LT4 engines** (e.g., Camaro SS, Corvette, Chevy Impala, GMC Yukon). This makes it a versatile choice for restomod builds and swaps.

2. **High-Quality Construction** TCI (Transmission Components Inc.) is known for producing durable, precision-machined flexplates that meet or exceed OEM specifications. The **dual-mass design** helps reduce torsional vibrations, improving drivability and longevity.

3. **Easy Installation** Unlike some aftermarket flexplates, the TCI 399606 is designed for straightforward installation, often requiring minimal modification to the bellhousing or flywheel interface. It includes the necessary **starter ring gear** and **flexplate bolts**, simplifying the process.

4. **Improved Performance & Smoothness** The dual-mass design helps dampen engine vibrations, leading to a **smoother shift experience** and reduced wear on the transmission. This is particularly beneficial for high-performance applications where engine torque can be significant.

5. **Warranty & Support** TCI offers a **limited warranty** on their flexplates, providing peace of mind for buyers. Their customer service and technical support are often praised for assisting with installation and troubleshooting.

6. **Cost-Effective Alternative to OEM** While not always cheaper than an original GM flexplate, the TCI unit is often **more affordable than a fully rebuilt OEM transmission** and provides better performance in many cases.

7. **Compatibility with Aftermarket Upgrades** Since the TCI flexplate is widely used in performance builds, it works well with **performance flywheels, clutch kits, and torque converter upgrades**, making it a flexible choice for enthusiasts.

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1. **Limited Availability & Lead Times** TCI products can sometimes have **longer lead times** due to high demand, especially for popular models like the LS-based flexplates. Buyers may need to order in advance or check stock levels carefully.

2. **Potential Fitment Issues** While the TCI 399606 is designed for GM 6-speed transmissions, **minor modifications may still be required** depending on the specific vehicle or engine setup. For example:

- Some applications may need **custom bolt patterns** or **spacer adjustments**.

- Vehicles with **heavy-duty or performance flywheels** might require additional alignment checks.

3. **Price Can Be High for Basic Use** While not excessively expensive, the TCI flexplate is **not the cheapest option** for a simple replacement. For stock applications, a **used OEM flexplate** might be a budget-friendly alternative (though less reliable).

4. **Requires Proper Installation** Like any flexplate, **incorrect installation** (e.g., improper bolt torque, misalignment) can lead to **premature failure or transmission damage**. This requires either **experience with manual transmissions** or professional help.

5. **Not a "Drop-In" Solution for All Swaps** If you're performing a **complete engine swap** (e.g., LS to a non-GM vehicle), you may need to verify **bellhousing compatibility** beyond just the flexplate. Some aftermarket bellhousings or adapters may be necessary.

6. **Dual-Mass vs. Single-Mass Trade-offs** While the dual-mass design reduces vibration, it can sometimes introduce **slightly more friction** compared to a single-mass flexplate. In very high-performance applications, some builders prefer a **single-mass flexplate with a performance flywheel** for reduced inertia.

7. **Warranty Limitations** TCI s warranty may not cover **damage from improper installation, misuse, or modifications**. Buyers should carefully review the warranty terms before purchase.

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### **Conclusion & Recommendation**

The **TCI 399606 flexplate** is an **excellent choice** for GM 6-speed automatic transmission builds, offering **superior quality, smooth operation, and broad compatibility**. It is particularly well-suited for:

- **Restomod projects** (e.g., LS engine swaps into older GM vehicles).

- **Performance applications** where vibration dampening is beneficial.

- **Builders who prioritize durability and ease of installation**.

- You need a **budget-friendly, no-frills replacement** (a used OEM flexplate may suffice).

- You re performing a **complex swap** that requires additional bellhousing modifications.

- You lack experience with **transmission installations** and cannot ensure proper fitment.

If you are **building or modifying a GM 6-speed automatic transmission** whether for a **stock, restomod, or performance application** the **TCI 399606 flexplate is a strong, reliable choice**. Ensure you:

1. **Verify compatibility** with your specific vehicle and engine setup.

2. **Follow installation guidelines carefully** to avoid issues.

3. **Consider professional installation** if you re unsure about alignment or bolt torque.

For most enthusiasts, the **benefits of a TCI flexplate durability, smoothness, and versatility outweigh the minor drawbacks**, making it a **highly recommended upgrade**.

Details:

American Express.

part #: 399606 prices

• $67.95-$85.30

specifications autotransmissionsgo:

• brand: Tci
• mpn: 399606
• part type: Transmission
• upc: 099998984348

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

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

seller autotransmissionsgo:

• city: , Ohio
• rating: 99.5%
• # reviews: 632478

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shipping autotransmissionsgo:

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• type: Fixed

offer autotransmissionsgo:

• sold: 0
• options: Ship-to-home
• availability: In Stock
• quantity: 1
• started: May 29, 2026

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