EVIL ENERGY AN6 to 1/4" NPSM Transmission Cooler Adapter Black 2PC — 6061-T6 CNC Aluminum

An AN6 male (9/16-18 UNF) to 1/4"-18 NPSM transmission cooler adapter — a CNC-machined 6061-T6 aluminum two-piece set designed to convert modern AN6 lines to older 1/4" NPSM transmission ports.

If you need to connect AN-style braided lines or aftermarket hose assemblies to factory or legacy transmission cooler ports, this EVIL ENERGY adapter pair provides a compact, corrosion-resistant solution. Machined from lightweight billet aluminum and finished in black, the fittings let you adapt AN6 male flare connections to older 1/4" NPSM female threads commonly found on transmissions such as TH350, TH400 and many automatic transmissions before 2007.

Will these adapters fit my transmission’s cooler ports?

They’re specifically sized to mate AN6 (9/16-18 UNF) male flare connections with 1/4"-18 NPSM female ports. The adapters were designed for the front and rear transmission lines used on numerous earlier automatic transmissions and are a direct fit where 1/4" NPSM ports are present.

• Thread conversion: AN6 male to 1/4"-18 NPSM female.
• Fits legacy transmissions like TH350, TH400, 700R4, 4L60E, AOD and related models.
• Sold as a 2-piece set for inlet and outlet lines.

How durable and leak-resistant are these fittings?

Manufactured from 6061-T6 billet aluminum and CNC-machined for consistent tolerances, the adapters resist rust and corrosion while remaining lightweight. Proper installation with compatible seals or thread tape will produce a reliable connection for fuel, oil, water and transmission fluid applications.

• Material: heat-treated 6061-T6 aluminum for strength and corrosion resistance.
• Precision CNC machining reduces thread mismatch and improves sealing surfaces.
• Compatible with transmission fluid, oil, fuel and coolant media when installed correctly.

How do I install an AN6 to 1/4" NPSM adapter in my cooling line?

Installation is straightforward: thread the 1/4" NPSM end into the transmission port and attach your AN6 hose or fitting to the male flare. Use a suitable sealing method for NPSM threads—such as PTFE tape or an appropriate sealant—and tighten to the manufacturer’s torque recommendations.

• Step 1: Clean threads and port seating area before assembly.
• Step 2: Apply PTFE tape or thread sealant compatible with transmission fluid.
• Step 3: Hand-start threads, then tighten with a wrench to proper torque; avoid over-tightening.

Which vehicles and systems commonly accept this adapter?

The adapter is intended for automatic transmissions and their cooling lines found on many American and aftermarket setups prior to 2007. It’s a common choice for restomods, performance swaps and repairs where AN fittings are preferred but the transmission still uses older NPSM ports.

• Direct compatibility: TH350, TH400, 700R4, 4L60E, 200-4R, AOD, TR-6060, 4R100, 4R70W.
• Also used in C5 applications and custom cooler loop builds.
• Useful in conversions where braided AN hoses are installed on stock transmissions.

Who is this for: This EVIL ENERGY adapter pair is suited to mechanics, restorers and performance enthusiasts who need a reliable, lightweight solution to join AN6 lines to older 1/4" NPSM transmission ports. If you’re upgrading cooling lines, doing a transmission service, or converting to AN hose for durability and appearance, the two-piece aluminum adapters give a tidy, corrosion-resistant interface for a wide range of transmissions and aftermarket setups.