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Start ShoppingCometic C9640 Twin Cam Transmission Gasket - High-Performance Replacement for Harley-Davidson
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Description
Ensure optimal transmission performance with Cometic's high-quality Twin Cam Transmission Gasket. This aftermarket replacement is engineered to deliver superior sealing reliability and durability for Harley-Davidson riders.
Key Features
- Proprietary Composite Material: Cometic's advanced fiber/paper blend provides exceptional sealing strength and resistance to heat, oil, and pressure.
- OEM-Grade Sealing Performance: Meets or exceeds original equipment manufacturer standards for leak-free operation.
- Individual Packaging: Sold separately for easy storage and precise installation.
- Twin Cam Compatibility: Specifically designed for Harley-Davidson Twin Cam transmission applications.
Why Choose This Product
Cometic's C9640 gasket offers peace of mind with its durable construction and reliable performance. Riders can trust this replacement to maintain proper transmission sealing, prevent fluid leaks, and support long-term engine health. The composite material resists degradation from engine fluids, ensuring consistent performance through thousands of miles. As an aftermarket solution, it provides an affordable alternative without compromising on quality or durability.
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Ensure optimal transmission performance with Cometic's high-quality Twin Cam Transmission Gasket. This aftermarket replacement is engineered to deliver superior sealing reliability and durability for Harley-Davidson riders.
Key Features
- Proprietary Composite Material: Cometic's advanced fiber/paper blend provides exceptional sealing strength and resistance to heat, oil, and pressure.
- OEM-Grade Sealing Performance: Meets or exceeds original equipment manufacturer standards for leak-free operation.
- Individual Packaging: Sold separately for easy storage and precise installation.
- Twin Cam Compatibility: Specifically designed for Harley-Davidson Twin Cam transmission applications.
Why Choose This Product
Cometic's C9640 gasket offers peace of mind with its durable construction and reliable performance. Riders can trust this replacement to maintain proper transmission sealing, prevent fluid leaks, and support long-term engine health. The composite material resists degradation from engine fluids, ensuring consistent performance through thousands of miles. As an aftermarket solution, it provides an affordable alternative without compromising on quality or durability.| SKU | GME5F769EA |
|---|---|
| MPN | C9640 |
| Brand | Cometic |
| Category | Gaskets/Seals |
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Frequently Asked Questions
Not all Twin Cam models use the same transmission cover gasket. You must verify fitment using a retailer’s fitment tool or by matching your OEM gasket part number to Cometic C9640. Do not rely only on the words “Twin Cam” in the description.
Most Cometic transmission cover gaskets are designed to seal dry on clean, flat surfaces. Follow the Harley‑Davidson service manual for your model; if it calls for a small dab of sealant at case joints, apply it only at those spots.
It is intended as a single‑use gasket. For best sealing and to avoid leaks, replace the gasket any time the transmission cover is removed.
Cometic engineers their gaskets to match OEM stack height and sealing characteristics. Any difference is typically minimal and does not require setup changes; however, always confirm any clearance‑sensitive components per your service manual.
When correctly installed, it should not change shifting feel or internal clearances. Its purpose is simply to seal the transmission cover against fluid leaks.
Installation Guide
Difficulty
Medium
Est. Time
1 hr 0 min
Tools Required
- Basic hand tools (metric/SAE socket set appropriate for Harley Twin Cam transmission cover fasteners)
- Torque wrench (inch‑lb or ft‑lb range per service manual spec)
- Gasket scraper or plastic razor blade
- Brake cleaner or non‑chlorinated parts cleaner
- Lint‑free rags
- Rubber mallet (optional, for gently freeing stuck cover)
- Drain pan (if removing cover that could release fluid)
Pro Tips
- Always confirm exact fitment by OEM part number cross‑reference or retailer fitment guide for your specific Twin Cam model and year
- Dry‑fit the gasket and cover first to confirm bolt‑hole alignment before applying any sealant (if your service manual calls for sealant at certain points). Many Cometic gaskets are intended to be installed dry.
- Lightly snug all bolts in a criss‑cross pattern and bring them to final torque in 2–3 stages using the torque spec from the Harley‑Davidson service manual
- Carefully scrape old gasket material with a plastic scraper to avoid gouging aluminum surfaces
- After installation, wipe everything clean and ride briefly, then check for seepage around the transmission cover
Common Mistakes to Avoid
- Re‑using old gasket instead of replacing
- Not cleaning mating surfaces completely before installing new gasket
- Using excessive RTV / silicone that can squeeze into the transmission
- Over‑torquing or unevenly torquing cover bolts, causing gasket extrusion or warping the cover
- Installing the gasket backwards or mis‑aligned with bolt holes
- Failing to verify shifter and linkage operation before final torque
Comparison vs Stock/OEM
Functionally equivalent to OEM Harley‑Davidson transmission cover gasket, designed as a direct replacement for Twin Cam applications where specified.
Improvements
- High‑quality Cometic gasket material aimed at consistent sealing and resistance to transmission fluid and heat
- Aftermarket pricing can be lower than OEM while maintaining comparable sealing performance
Considerations
- Must be correctly cross‑referenced to the OEM part number for your specific Twin Cam model and year
- Does not include hardware; re‑use OEM bolts if in good condition or replace separately
Durability & Warranty
Expected Lifespan
Intended to last the service life of the transmission cover installation when correctly torqued and not disturbed; replace whenever the cover is removed.
Maintenance
Periodically inspect the transmission area for seepage or leaks, especially after the first few rides post‑installation.
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