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  3. CLASSIC INSTRUMENTS SN17G18

CLASSIC INSTRUMENTS SN17G18 Speedometer Gear Transmission 090127765357

fits make: Ford.

Sn17g18 Classic Instruments Speedometer Driven Gear For Ford Transmissions

( Brand: Classic Instruments ), ( Manufacturer Part Number: SN17G18 ), ( Part Type: Speedometer Gear Transmission ), ( Country Of Origin: Usa ), ( UPC: 090127765357 )

Review CLASSIC INSTRUMENTS Speedometer Driven Gear Ford Transmissions

The **SN17G18 Speedometer Gear** is a meticulously crafted, high-performance transmission component designed exclusively for Ford vehicles equipped with the iconic **C4 automatic transmission**, a workhorse known for its durability and widespread use in classic Mustangs, Thunderbirds, Fairlanes, and other muscle cars from the 1960s through the early 1980s. This precision-machined gear serves as the critical link between the transmission s output shaft and the vehicle s speedometer cable, translating rotational movement into accurate speed readings on the dashboard. Crafted from **high-grade steel** and heat-treated for optimal strength and wear resistance, the SN17G18 gear is engineered to withstand the rigors of daily driving, high-performance applications, and even modified setups where increased torque or revving habits may stress the transmission. Its **17-tooth design** is a hallmark of the C4 s original speedometer system, ensuring seamless compatibility with stock speedometer cables, aftermarket gauges, and modern digital speedometer conversions. The gear s **smooth, polished teeth** and precision-ground bearing surface minimize friction and backlash, reducing wear on both the gear itself and the transmission s internal components, thereby extending the life of the entire drivetrain. Whether restoring a vintage Ford to its original glory or building a modern hot rod with classic charm, the SN17G18 speedometer gear delivers the reliability and accuracy needed to keep the speedometer functioning flawlessly no matter how fast or hard the vehicle is driven. Its **universal fit** across a vast array of Ford applications, from the 1964-1991 Mustang to the 1967-1977 Thunderbird, makes it an indispensable part for enthusiasts seeking both authenticity and performance in their restoration or customization projects.

### Pros and Cons of Buying a Classic SN17G18 Speedometer Gear for Ford Transmissions

#### **Pros:**

1. **Compatibility** The SN17G18 speedometer gear is designed specifically for Ford transmissions, including models like the C4, C6, and early C6 (in some cases). This ensures a direct fit without the need for extensive modifications, making it a straightforward upgrade or replacement option.

2. **Reliability** As a classic, well-tested component, the SN17G18 gear is known for its durability and consistent performance. Many mechanics and enthusiasts trust this gear for its longevity, especially in applications where the stock gear may wear out prematurely.

3. **Accuracy** The SN17G18 gear is often praised for providing more accurate speedometer readings compared to some aftermarket alternatives. This is particularly useful for those who rely on precise speedometer calibration, such as in racing or high-performance applications.

4. **Ease of Installation** Since it is a standard replacement part for many Ford transmissions, swapping it out typically requires minimal tools and time. Most users can install it themselves with basic mechanical knowledge, reducing labor costs.

5. **Availability** While not as commonly stocked in big-box auto parts stores, the SN17G18 gear is still relatively easy to source from specialty Ford transmission suppliers, online marketplaces, or through Ford-focused forums. It is not an obscure part, so finding a replacement is generally feasible.

6. **Compatibility with Upgrades** If you are working on a transmission build or upgrade (e.g., adding a tachometer or modifying the speedometer circuit), the SN17G18 gear can integrate smoothly with other classic Ford transmission components, making it a versatile choice.

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#### **Cons:**

1. **Limited Modern Compatibility** The SN17G18 gear is designed for older Ford transmissions (pre-1990s in many cases) and may not work with newer models or transmissions that use different speedometer wiring or mounting configurations. This could require additional modifications or adapters.

2. **Potential for Wear** Like any mechanical part, the SN17G18 gear can wear out over time, especially if the transmission fluid is not changed regularly or if the gear is subjected to high stress (e.g., aggressive driving or racing). Replacement may still be necessary after extended use.

3. **Cost** While not excessively expensive, the SN17G18 gear can be more costly than generic or aftermarket alternatives, particularly if purchased from a reputable supplier. Prices may also fluctuate depending on demand and availability.

4. **Stock vs. Aftermarket Confusion** Some users may confuse the SN17G18 with other speedometer gears (e.g., SN17G17 or SN17G19), which are not interchangeable. Mixing up part numbers can lead to compatibility issues or incorrect speedometer readings, so careful verification is required.

5. **Limited Customization** If you are looking for a gear with a different gear ratio (e.g., for a tachometer or modified speedometer calibration), the SN17G18 may not offer the flexibility of some aftermarket gears that come in multiple ratios. Custom machining may be required for non-standard applications.

6. **Source Dependability** While the part itself is reliable, the quality of the source can vary. Purchasing from an unknown or untrusted seller may result in counterfeit or low-quality replicas that fail prematurely. Always buy from established suppliers or trusted vendors.

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### **Conclusion:**

The SN17G18 speedometer gear is a solid choice for Ford transmission applications, particularly for classic models or those seeking a reliable, accurate, and easy-to-install replacement. Its compatibility with older Ford transmissions and reputation for durability make it a favorite among enthusiasts. However, its limited compatibility with newer systems, potential for wear, and higher cost compared to generic alternatives should be considered. If you are working on a project car with a compatible transmission and prioritize accuracy and ease of installation, the SN17G18 is a worthwhile investment. For modern applications or those requiring custom gear ratios, alternative options may need to be explored.

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### **Recommendation:**

If you are restoring or modifying a classic Ford transmission (e.g., C4, C6) and need a speedometer gear that is both reliable and accurate, the SN17G18 is an excellent choice. Purchase it from a reputable supplier (such as RockAuto, Summit Racing, or a trusted Ford transmission specialist) to ensure authenticity and quality. Verify the exact application compatibility with your transmission model before purchasing, as some variations may require additional adapters or modifications.

For newer Ford transmissions or applications requiring non-standard gear ratios, consider consulting a transmission specialist or exploring aftermarket gears designed for modern systems. Always pair the gear replacement with a transmission fluid change to maximize its lifespan and performance.

Details:

American Express.

part #: sn17g18 prices

  • $24.57-$45.32

specifications boosttempgauges:

  • for makes: Ford
  • brand: Classic Instruments
  • mpn: Sn17g18
  • part type: Speedometer Gear Transmission
  • country of origin: Usa
  • upc: 090127765357

payments boosttempgauges:

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

shipping boosttempgauges:

  • class: Standard
  • type: Fixed
  • cost: $15.99
  • transit: 3-7 Days
  • service: Standard

seller boosttempgauges:

  • # reviews: 634685
  • rating: 99.5%
  • city: , Ohio

general boosttempgauges:

  • Interior Parts Accessories > Gauges > Individual Gauges
  • condition: New

offer boosttempgauges:

  • started: June 10, 2026
  • sold: 0
  • quantity: 1
  • options: Ship-to-home
  • availability: In Stock

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  • paid by: Seller
  • policy: Returns Accepted
  • time: 30 Days
for makes: ford, part type: speedometer gear transmission, country of origin: usa,
category: auto parts > interior parts accessories > gauges > individual gauges, sku: 21028261181534813,
Classic Instruments SN17G18 Is Similar To:
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5 offers $24.57–$45.32 USD
  • New. Offer #1 priced at $45.32 + $0.00 shipping estimate = $45.32* total. Classic Instruments .FREE SHIPPING
  • New. Offer #2 priced at $24.57 + $11.95 shipping estimate = $36.52* total. Compatible with Ford Transmission - 18-Tooth Gear; Replacement 18-tooth speedometer driven gear - includes clip.;.+$11.95 shipping
  • New. Offer #3 priced at $24.57 + $11.95 shipping estimate = $36.52* total. Retaining clip included. Ford 18-Tooth Gear .+$11.95 shipping
  • New. Offer #4 priced at $24.57 + $15.99 shipping estimate = $40.56* total. Speedometer Driven Gear, Ford Transmissions, 18-Tooth, Sold Individually Classic Instruments 18 Tooth Ford Speedo Gear.+$15.99 shipping
  • New. Offer #5 priced at $34.85 + $10.02 shipping estimate = $44.87* total. +$10.02 shipping

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