GM GENUINE PARTS 85126475 Gear Kit

( Brand: Gm Genuine Parts ), ( Manufacturer Part Number: 85126475 ), ( Genuine Oem: Yes ), ( Manufacturer Warranty: 1 Year ), ( Fitment Type: Direct Replacement ), ( Replaces Part Number: 86772562 ), ( Type: Steering, Gear And Related Components )

Review GM GENUINE PARTS Remanufactured Gear Kit fits FS

The **GM 85126475 FS Gear Kit** is a high-performance, precision-engineered transmission gearset designed exclusively for General Motors (GM) vehicles equipped with the **6L90E automatic transmission**, commonly found in full-size trucks, SUVs, and heavy-duty applications such as the Chevrolet Silverado, GMC Sierra, and GMC Yukon. This aftermarket gear kit is meticulously crafted to enhance shifting smoothness, reduce wear on internal transmission components, and improve overall drivetrain efficiency, making it an ideal upgrade for enthusiasts seeking optimized performance or those looking to extend the lifespan of their transmission. The kit features a **full set of synchros, clutches, and reverse idler gears**, all manufactured to exceed OEM specifications, ensuring seamless engagement and reduced grinding during gear shifts. Engineered with high-quality materials, including hardened steel and precision-machined components, the 85126475 FS gear kit is built to withstand the demands of heavy loads, towing, and aggressive driving conditions, providing a noticeable improvement in shift quality and durability compared to stock parts. Whether installed in a daily driver, a towing application, or a performance-oriented vehicle, this gear kit delivers a refined, responsive transmission experience while minimizing the risk of premature failure in critical components. Compatible with a range of GM applications, this kit is a trusted choice for mechanics and DIY enthusiasts alike, offering a cost-effective solution to restore or enhance transmission performance without compromising reliability.

The GM 85126475 FS Gear Kit is a popular aftermarket gearset designed for General Motors vehicles, particularly those with the LS engine family (such as the LS1, LS2, LS3, LS7, or LT1). Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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### **Pros of the GM 85126475 FS Gear Kit**

1. **High-Quality Materials and Craftsmanship**

The kit is manufactured by GM Performance Parts, a reputable brand known for durability and precision engineering. The gears are made from high-strength steel, designed to withstand heavy loads and prolonged use, especially in performance applications.

2. **Optimized for Performance**

This is a "FS" (Full Sequential) gearset, meaning it is designed for high-performance applications, including drag racing, street tuning, and track use. The gear ratios are engineered to maximize power delivery, reduce RPM, and improve throttle response, which is ideal for modified engines pushing beyond stock specifications.

3. **Compatibility with LS Engines**

The kit is specifically designed for GM LS engines, ensuring a seamless fit with stock and aftermarket transmissions (such as the Tremec TR3300, Tremec TR6060, or GM 6-speed manual transmissions). It is commonly used in applications like the LS1, LS2, LS3, LS7, and LT1, making it versatile for a wide range of vehicles.

4. **Durability and Longevity**

The gears are heat-treated and precision-ground to minimize wear and tear. This kit is often used in aggressive driving scenarios, including drag racing, where durability is critical. Many users report that these gears last for tens of thousands of miles with proper maintenance.

5. **Easy Installation**

The kit comes with all necessary components, including synchronizers, bearings, and seals, and is designed for straightforward installation. While some mechanical skill is required, it is generally considered easier to install than custom or aftermarket gearsets that require additional machining or modifications.

6. **Cost-Effective for High-Performance Use**

Compared to custom gearsets or high-end aftermarket options, this kit offers a balance between performance and affordability. It is a popular choice for builders on a budget who still want reliable, high-performance ratios.

7. **Widely Available and Supported**

As a GM part, it is easy to find through authorized dealers, online retailers, and performance shops. Additionally, there is a wealth of information, forums, and tutorials available for installation and troubleshooting.

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### **Cons of the GM 85126475 FS Gear Kit**

1. **Not Ideal for Stock or Mildly Modified Engines**

This gearset is designed for high-performance applications and may feel too "tall" (low gearing) for stock or mildly modified engines. If your engine is not significantly modified, the gears may cause excessive RPM at highway speeds, leading to discomfort or potential engine stress if not properly tuned.

2. **Limited Ratio Options**

The FS gearset comes with a fixed set of ratios, which may not be optimal for every application. If you require specific ratios for a particular use case (e.g., drag racing, street driving, or track use), you may need to pair it with a different gearset or modify the transmission further.

3. **Potential for Increased Wear on Other Transmission Components**

While the gears themselves are durable, the aggressive ratios can increase stress on synchronizers, bearings, and the input/output shafts. This may lead to premature wear if the transmission is not properly maintained or if other components are worn out.

4. **Requires Proper Lubrication and Maintenance**

Like any high-performance gearset, the FS kit demands high-quality transmission fluid and regular maintenance. Using the wrong fluid or neglecting maintenance can reduce the lifespan of the gears and other transmission components.

5. **Not Suitable for All LS Engine Applications**

While compatible with most LS engines, some variations (such as the LS9 or LT4) may require additional modifications or different gearsets to fully optimize performance. Always verify compatibility with your specific engine and transmission setup.

6. **Installation Can Be Challenging for Beginners**

While the kit is designed for ease of installation, it still requires mechanical skill, the right tools, and patience. Mistakes during installation (e.g., improperly seating gears or misaligning shafts) can lead to transmission failure or damage.

7. **Potential for RPM Spikes**

The gearing in this kit can cause the engine to rev higher than desired at certain speeds, which may not be ideal for daily driving or applications where smooth power delivery is preferred. This can be mitigated with a proper tuning strategy or additional modifications (e.g., a taller rear axle).

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### **Conclusion**

The GM 85126475 FS Gear Kit is an excellent choice for enthusiasts looking to maximize performance in their LS-engine-powered vehicles, particularly for drag racing, track use, or heavily modified street applications. Its durability, compatibility with LS engines, and ease of installation make it a popular and reliable option. However, it is not suitable for stock or mildly modified setups, as the gearing can lead to excessive RPM and discomfort. Additionally, proper maintenance and lubrication are essential to ensure longevity.

For users who prioritize high-performance driving and are willing to invest in maintenance, this gearset delivers strong results. Those with stock or lightly modified setups may find it too aggressive and should consider alternative gearsets or ratios.

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### **Recommendation**

- You have a significantly modified LS engine (e.g., forced induction, high compression, or substantial power gains).

- Your primary use involves drag racing, track driving, or aggressive street performance.

- You are comfortable with maintenance and proper lubrication practices.

- You want a reliable, high-quality gearset from a reputable manufacturer with broad compatibility.

- Your engine is stock or only mildly modified, and you prefer smoother, lower-RPM driving.

- You are unsure about installation or maintenance requirements and lack mechanical experience.

- You require custom or non-standard gear ratios that this kit does not provide.

- You plan to use the vehicle primarily for daily commuting or highway driving without modifications.

- For stock or mildly modified setups, consider a stock or mildly modified gearset (e.g., GM stock gears or a "street" gearset like the 85126474).

- For drag racing, explore custom gearsets or aftermarket options like those from **Tremec, Jegs, or Summit Racing** that offer more ratio flexibility.

- If you need a balance between performance and comfort, look into a "compromise" gearset that offers a middle ground between stock and full sequential ratios.

Ultimately, the GM 85126475 FS Gear Kit is a strong performer for the right application, but it is not a one-size-fits-all solution. Always match the gearset to your engine s power output, driving style, and intended use.

Details:

Parts must be resalable and in the original packaging. Despite what the images or illustrations may show, all parts are sold individually. GM Parts America. Despite what images and illustrations may show, all parts are sold individually.

Such as trim, engine size, color, etc. ATTENTION: The catalog displayed is a generic consumer-friendly application and does not decipher all the options your vehicle may have been built with. Electrical parts are not returnable under any circumstance. Shipping Carrier substitutions may be made at our determination in an attempt to reduce shipping cost.

Scottsdale, AZ 85260. 8585 E Frank Lloyd Wright Blvd.

part #: 85126475 prices

• $1164.25-$1172.78

specifications steragebo:

• for models: Fs
• brand: Gm Genuine Parts
• mpn: 85126475
• genuine oem: Yes
• manufacturer warranty: 1 Year
• fitment type: Direct Replacement
• replaces part number: 86772562
• type: Steering, Gear And Related Components

returns steragebo:

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

shipping steragebo:

• cost: $73.36
• transit: 3-6 Days
• type: Fixed
• service: Standard
• class: Standard

payments steragebo:

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

seller steragebo:

• rating: 99.6%
• # reviews: 24000
• city: Scottsdale, Arizona

general steragebo:

• Car Truck Parts Accessories > Steering Suspension > Gearboxes, Rack Pinions
• condition: Remanufactured

offer steragebo:

• started: May 10, 2026
• availability: In Stock
• sold: 0
• options: Ship-to-home
• quantity: 2

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