The aFe 44-FF025 is a ProGUARD HD fuel/water separator filter set for the 6.7L Power Stroke V8 diesel. It is actually two elements in one service job: the primary water separator on the driver-side frame rail, and the secondary fine filter up in the engine bay. aFe lists Motorcraft FD4625AA and Wix WF10458 as cross-references, and its specifications show that the filter and coupler are both included. aFe presents the unit as a direct OE-style replacement, so it is designed to ensure a proper fit and hassle-free installation.
Choosing this kit over stock comes down to water control and fuel flow. The primary's job is separating emulsified water out of the fuel, the failure mode behind most CP4.2 failures, while the secondary catches the remaining fines. Keeping that separator clean is the practical way to protect a CP4 high-pressure pump, and aFe's stated goal is fuel delivery with minimal restriction and strong filtration. Search terms this kit answers include 6.7 Powerstroke fuel water separator upgrade, FD4625 filter replacement, and 2017 F-250 CP4 pump protection.
The manufacturer describes the 44-FF025 as a direct OE replacement, and it lists Motorcraft FD4625AA and Wix WF10458 as cross-references. Confirm your truck's model year against aFe's fitment list before ordering, because published year ranges differ between sources.
The manufacturer's specifications list the filter and coupler as included. Owners on user forums describe the service as replacing both the frame-rail separator and the engine-bay secondary element.
The 44-FF014 is a separate ProGUARD D2 line for 2011-2016 trucks, so it does not apply to 2017+ 6.7L fitment. Verify the part number against your truck before purchase.
Owners on user forums treat this as a manageable home job, but expect fuel spillage and plan for it. Drain the housing first: just drain the filter housing with the thumb drain, loosen the bottom plate bolts and it will pull off with the filter. On the frame-rail unit, the housing has a yellow quarter-turn drain valve on its underside so you can drop accumulated water. Unplug the water-in-fuel sensor before draining, since unplug the WIF sensor first (press the center tab). Forum posters also report the lower element can bind in its housing, so wiggle and pull gently rather than forcing it. Watch for a large number of shiny metal particles in the housing, which can signal early CP4 pump wear. After assembly, owners recommend cycling the key several times to prime the system before starting, turning the key to the on position for 30 seconds, six times.
