EVIL ENERGY AN6 to 1/4" NPSM Transmission Cooler Adapter Set — Silver Aluminum, Short & Long Pair, 6061-T6 CNC

These EVIL ENERGY 6AN male flare to 1/4" NPSM adapters convert AN6 transmission cooler lines to factory 1/4" NPSM ports for 4L80E and many LS-series transmissions, supplied as a pair in durable anodized 6061-T6 aluminum.

When upgrading or repairing transmission cooler lines on GM 4L80E and related LS-platform vehicles, you need a compact, corrosion-resistant adapter that seals reliably and installs without fussy modifications. These EVIL ENERGY fittings are CNC-machined with a 37-degree AN sealing flare on the male side and a 1/4"-18 NPSM threaded side designed for factory-style ports. They come in two lengths to suit front and rear cooler ports and are finished with anodizing to resist oil and environmental corrosion.

How do these adapters fit my 4L80E or LS-series transmission?

The adapters are sized AN6 (9/16"-18 UNF) male on the AN side and 1/4"-18 NPSM on the threaded side, matching common transmission cooler port standards. They’re supplied as short and long lengths to clear firewall and case geometry in most installations without bending or re-routing lines.

• AN side: 9/16"-18 UNF male with a 37-degree sealing flare for AN hoses.
• NPSM side: 1/4"-18 NPSM threads to match factory cooler ports.
• Two lengths: short for front ports, long for rear ports to avoid interference.
• Compatible with many GM engines and transmissions including 4L80E.

What materials and construction ensure durability?

These fittings are machined from 6061-T6 aluminum for a high strength-to-weight ratio and resistance to cracking under vibration. An anodized finish adds a protective oxide layer that stands up to oil exposure and road salt, extending service life in harsh underhood conditions.

• 6061-T6 aluminum body for lightweight strength.
• CNC machining for precise thread fit and sealing surfaces.
• Anodized finish for corrosion and oil resistance.
• Hexagonal body design for secure wrench installation without rounding.

Will these adapters seal reliably with AN hoses and transmission ports?

The male AN side uses a 37-degree flare — the standard sealing interface for AN fittings — providing a metal-to-metal seat when mated to AN female fittings. The NPSM threaded side is designed to thread into factory cooler ports; proper torque and thread condition are important for a leak-free installation.

• 37-degree AN flare ensures proper metal-seat sealing with AN female fittings.
• NPSM threads match factory port dimensions; use appropriate thread lubricant or sealant if recommended.
• Hex shape allows controlled torque to prevent over-tightening or galling.
• Two-piece set covers front and rear cooler port geometries to minimize stress on hoses.

Who is this for: These EVIL ENERGY AN-to-NPSM adapters are made for automotive enthusiasts, mechanics, and custom builders who are installing aftermarket AN transmission cooler lines on GM 4L80E transmissions or LS-platform engines. Choose these fittings if you want a CNC-machined, anodized aluminum adapter set that matches factory threaded ports, provides reliable AN flare sealing, and comes in lengths suited for front and rear cooler locations. They’re particularly useful when upgrading cooling capacity, repairing corroded factory fittings, or converting to braided AN hose in performance or restoration projects.