Bevinsee transmission cooler adapter plate — 6AN fittings, billet aluminum, fits GM 6L80E/6L90E/8L90E

Bevinsee's billet-aluminum transmission cooler adapter plate converts GM 6L80E/6L90E/8L90E transmission ports to 6AN fittings with a preassembled gasket and mounting hardware.

If you need to run an external transmission oil cooler or aftermarket 6AN lines on recent GM 6- and 8-speed automatic transmissions, this adapter plate provides a compact, factory-replacement style solution. CNC-machined from billet aluminum and finished with a black anodized coating, the adapter is built to resist corrosion while matching the precision fitment required for modern GM transmissions. It arrives with 6AN fittings, sealing gasket and a mounting bolt already installed to simplify installation.

How does this adapter plate let me add an external transmission cooler?

This adapter replaces the stock cooler line interface and provides standard 6AN ports so you can attach aftermarket 6AN hose and an oil cooler. It maintains a sealed connection using the supplied gasket and mounting bolt to prevent leaks and create a tight mating surface with the transmission housing.

• Directly converts factory ports to two 6AN female fittings for inlet and outlet lines.
• Includes gasket and bolt preinstalled for a ready-to-fit assembly.
• Compatible with 6L80E, 6L90E and 8L90E GM transmissions.

Will this fit my GM 6L80E, 6L90E or 8L90E transmission?

The adapter is specifically designed for the later-model GM transmissions listed and uses the factory mounting interface for a snug replacement. Because it’s CNC-machined to OEM-style dimensions, it lines up with the stock port locations; still verify your transmission variant and model year before ordering to ensure compatibility.

• Made for 6L80E, 6L90E and 8L90E model transmissions.
• CNC-machined for accurate alignment with factory port geometry.
• Check vehicle build sheet or transmission code to confirm match.

What are the construction and corrosion protection details?

Construction uses billet aluminum for strength and light weight, then a black anodized finish is applied to improve surface hardness and resist oxidation. The precision CNC machining delivers consistent sealing surfaces and thread fits, helping avoid leaks when installed with the supplied gasket.

• Billet aluminum body for durability and thermal stability.
• Black anodized surface treatment for corrosion resistance and a clean look.
• CNC machining ensures accurate port alignment and smooth sealing faces.

How simple is installation and what hardware is included?

The Bevinsee adapter comes with 6AN fittings, a rubber/metal gasket and a mounting bolt already assembled so you can swap it into the transmission port and connect your 6AN lines without sourcing extra parts. Standard hand tools are typically all that’s required; torque to the transmission manufacturer’s spec to ensure a secure seal.

• Preassembled 6AN fittings and gasket minimize assembly time.
• Single mounting bolt included for factory-style replacement installation.
• Requires compatible 6AN hoses and cooler hardware (not included).

Who is this for: This adapter plate is intended for vehicle owners, performance shops and DIY mechanics upgrading cooling on GM vehicles equipped with 6L80E, 6L90E or 8L90E transmissions. It’s especially useful for drivers adding an external cooler, converting to reusable 6AN lines, or replacing a worn factory cooler manifold with a durable billet component. Verify transmission model and have proper 6AN hoses and fittings ready before beginning installation.