If you tow trailers, haul heavy loads, or drive your F-150 in hot climates, your transmission works harder than most people realize — and it relies on more than just your radiator to stay cool. That's where the auxiliary transmission oil cooler comes in, and when it fails, the symptoms can be easy to misdiagnose.
What the Auxiliary Cooler Actually Does
Your F-150's automatic transmission generates significant heat, especially under load. While your radiator has a built-in transmission cooler, trucks with certain configurations also use a separate auxiliary cooler mounted near the front of the vehicle to provide extra cooling capacity. This keeps transmission fluid at a safe operating temperature, which is critical for smooth shifting and long-term transmission health.
Signs Your Auxiliary Cooler Is Failing
- Transmission temperature warnings, especially while towing or in hot weather
- Visible fluid leaks near the front of the truck, below the radiator
- Rough, delayed, or hesitant shifting under load
- Reduced towing performance or transmission feeling "sluggish" when hot
If you're noticing any of these, especially during towing season, it's worth inspecting the auxiliary cooler before assuming a bigger transmission issue is at play.
Which Trucks Does This Affect?
This applies to Ford F-150 trucks with the 5.0L V8 and 6-speed automatic transmission, model years 2015 through 2019, specifically those without the Heavy Duty Towing Package (which uses a different cooler).
Can You Replace It Yourself?
Yes — this is a manageable DIY job for most owners. It involves draining some transmission fluid and reconnecting cooler lines, but doesn't require specialty tools.
What You'll Need
- Replacement auxiliary cooler (Ford part FL3Z-7A095-B)
- Basic hand tools, drain pan
- 30-45 minutes
Why Buy From Us
Every auxiliary cooler we sell comes with a free step-by-step installation video — so you can mount it and connect the lines correctly without guessing. We ship fast within the US and stand behind fitment for your specific F-150 configuration.
👉 Shop the Ford F-150 Auxiliary Transmission Oil Cooler here