Foruly Transmission Cooler Bypass Plug for Silverado/Sierra 6L80 6L90 8L90 — OE-fit, corrosion-resistant plug

Foruly's Transmission Cooler Bypass Plug replaces the factory cooler loop on Silverado/Sierra 6L80, 6L90 and 8L90 transmissions to streamline fluid routing and improve cooling efficiency.

Designed as a direct-fit, plug-and-play replacement for specific GM transmission cooler lines, this Foruly bypass plug removes the stock external cooler loop and redirects fluid through the transmission’s internal cooling path. The result is a simplified plumbing setup that reduces leak points and helps maintain consistent fluid flow under towing, hauling, or high-load conditions.

How does the bypass plug change my Silverado or Sierra’s cooling setup?

When installed, the Foruly bypass plug isolates the external cooler loop and routes transmission fluid through the internal cooler passages. That reduces the number of hose connections and potential leak sources while preserving effective heat transfer inside the transmission assembly.

• Eliminates external cooler loop for simpler fluid routing
• Reduces hose and fitting count to lower leak risk
• Maintains internal fluid flow compatible with OE design

Will this plug fit my 6L80, 6L90 or 8L90 transmission without modifications?

Yes — Foruly engineered this bypass plug to match OE dimensions used on many Silverado and Sierra models equipped with 6L80, 6L90 and 8L90 transmissions. The plug installs into the existing cooler line fitting using the factory port locations, so no custom fabrication is required.

• Engineered to OEM fitment standards for select GM models
• Plug-and-play installation—no special tools needed
• Seals to the original cooler port for a leak-free connection

How durable is the Foruly bypass plug under heavy use?

The bypass plug is constructed from corrosion-resistant materials designed for the operating environment of engine bays and transmission plumbing. It’s built to withstand repeated thermal cycling, road vibration, and typical towing demands when installed correctly.

• Corrosion-resistant finish for long service life
• High-strength materials that resist cracking and deformation
• Designed for repeated installation and removal if servicing is required

How easy is the installation and what should I expect during the process?

Installation is straightforward for anyone comfortable working under the vehicle or alongside the radiator and cooler lines. The job usually requires disconnecting the cooler hose, seating the plug in the factory port, and tightening to OE torque; always follow vehicle service procedures for safety and leak-checking.

• Simple insert-and-secure design—no cutting or welding
• Fits existing hose/fitting interface to minimize tools needed
• Quick visual leak check recommended after first drive

Who is this for? The Foruly Transmission Cooler Bypass Plug is aimed at Silverado and Sierra owners with 6L80, 6L90 or 8L90 transmissions who prefer a simplified cooling circuit—particularly those who tow frequently, modify cooling plumbing, or want to reduce external leak points. It’s suitable for DIY mechanics, fleet technicians, and performance builders who need a reliable, OE-compatible plug that simplifies transmission cooler plumbing without altering internal hydraulic function.