6R140 Transmission Cooler

This listing is for the cooler connection, not a cooler core: a new pair of -8AN transmission oil cooler fittings that mount at the cooler ports on the case of a Ford 6R140, and also on the 6R80, 6R100, 10R80, 10R100 and 10R140. They are made for builders and owners who want to run braided or hose-and-AN cooler lines instead of the factory push-in steel tubes, whether that is a Super Duty getting a larger auxiliary cooler, a truck with damaged factory lines and no good replacement path, or a 6R140 going into a different chassis as a swap. The fittings include NPT ports, and each one is new.

What the cooler fittings do on a 6R140

From the factory, the 6R140 cooler tubes push straight into bores in the transmission case and are clamped by a single bolted hold-down plate. There is no thread at the case and no collar. That works well when the tubes and plate stay perfectly aligned, but Ford issued a service message after some 2017 Super Duty trucks leaked at that joint from tube or plate misalignment. The other end of the factory line uses a plastic quick-connect at the cooler. When you move away from the factory lines entirely, you need a way to turn those case bores into a standard fitting. These adapters give you a -8AN male end at each port so any properly sized AN line can carry fluid to and from the cooler.

Cooler flow matters on this unit. The 6R140 is rated for continuous operation at 250 degrees F, and a heavy truck towing in summer can push it there. Restricting the circuit with undersized lines or sharp bends cuts the converter-out flow that keeps the fluid alive.

Symptoms that bring owners to this part

• Fluid weeping from behind the pan rail or down the bellhousing at the case cooler connection
• A factory tube that is kinked, corroded through or chafed where it runs along the frame
• Planning an auxiliary or larger stacked-plate cooler that needs AN plumbing
• A 6R140 or 10-speed being installed in a vehicle that never had factory lines for it
• Transmission temperatures climbing while towing after a line repair that changed the routing

How to confirm before you buy

If you are chasing a leak, clean the case connection and the cooler end, then run the truck until fluid reappears so you know which end is actually leaking. A case-side leak on an otherwise good truck is often fixed by re-seating the tubes square in their bores and installing a new hold-down bolt and washer at 18 lb-ft. Our 6R140 cooler line replacement guide walks through that repair and the quick-connect at the cooler. If the truck runs hot with no external leak, do a cooler flow test first; low flow from inside the transmission will not be cured by new fittings. The 6R140 pump failure guide covers the internal causes.

Fitment

These fittings are listed for the Ford 6R140 used in 2011-2019 F-250, F-350, F-450 and F-550 Super Duty trucks, plus the 6R80, 6R100, 10R80, 10R100 and 10R140 families. They replace the factory push-in tube connection, so they are for custom or aftermarket line setups, not a direct swap with Ford's quick-connect lines. Check your case cooler ports against the photo, and if you want a second look, send us your year and VIN. Browse the rest of the unit on our 6R140 parts page.

Install notes

• Lower the fluid level before opening the cooler circuit, or a full system will dump fluid as soon as the tubes come out.
• Clean the case bores and make sure each fitting is fully seated and secured before you hang any line weight on it.
• Use -8AN line rated for transmission fluid and heat, keep bends gentle, and support the lines so engine and chassis movement is not carried by the fittings.
• Seal the NPT ports with a plug or a sender rated for ATF. Use thread sealant on NPT threads only, never on the AN flare.
• Refill with MERCON LV, set the level hot, then recheck every joint after the first heat cycle.

A line job is a good time for fresh fluid and filters. If the truck overheated before, inspect the fluid and consider a 6R140 master rebuild kit if it came out burnt, or a 6R140 valve body if line pressure bore wear is the cause of low cooler flow.

Is this an actual transmission cooler?

No. This is a pair of -8AN cooler fittings that mount at the transmission case ports. You pair them with AN lines and your factory or aftermarket cooler.

Will these fit my 10R80 or 6R80 too?

Yes, they are listed for the 6R80, 6R100, 6R140, 10R80, 10R100 and 10R140. Compare the case cooler ports with the photo, or send us your year and VIN to double-check.

Can I connect them to the factory Ford cooler lines?

No. The factory lines push into the case and use a quick-connect at the cooler. These fittings are for AN-style line setups such as an auxiliary cooler, custom routing or an engine and transmission swap.

What size line do I need?

The fittings have -8AN ends, so use -8AN line and hose ends rated for automatic transmission fluid and heat.

What are the NPT ports for?

They give you a threaded port in the cooler circuit, commonly used for a temperature sender or gauge. Plug any port you do not use with an ATF-safe plug.

What fluid does the 6R140 use after the job?

Ford specifies MERCON LV for the 6R140. Top off and set the level with the fluid hot after the lines are connected.

• 6R140 Cooler Line Replacement Guide
• 6R140 Pump Failure Symptoms and Replacement
• Ford 6R140 TorqShift Problems and Service: A Rebuilder's Guide
• 6R140 Pressure Control (EPC) Solenoid Symptoms