Ford 4R100 Front Pump Assembly PWM Cast RFF8 1998-Up F250 F350 7.3L Powerstroke

Ford 4R100 Front Pump Assembly PWM Cast RFF8 1998-Up F250 F350 7.3L Powerstroke

Used OEM unit pulled from an inspected donor transmission, cleaned and visually inspected before listing. Photos show a representative unit of this exact part and variant — see the fitment and casting notes below to confirm your match.

• SKU: F-4R100-PM-U-01
• Includes: One good used OE 4R100 front pump assembly, PWM type, 12-bolt, pump casting RFF8, for units using the stamped steel coast clutch drum, as shown in the photos. Good used — no gasket, seal, bushing or O-ring included; replace all seals and bushings at install.
• Warranty: 30-day return-or-replace after delivery
• Shipping: UPS Ground from our Tennessee warehouse, 2 business day handling

OEM / interchange references (verify against your casting/tag):

• RFF8
• 36500DB

Fits (engine/year matters — read carefully): Ford 4R100 four-speed automatic, 1998 and up, PWM applications: F-250, F-350 and Super Duty, Excursion and E-Series with the 7.3L Power Stroke diesel, 6.8L V10 or 5.4L gas as equipped.

Important: Two things must match. First, PWM versus NON-PWM: this is the PWM pump, and the two are not interchangeable across the 1998 changeover. Second, it is the version for the STAMPED STEEL coast clutch drum — units built with the cast-iron coast clutch drum take a different pump. Check your drum type and the RFF8 casting against the photos before ordering. Sold as a used assembly; fit new seals and bushings.

Before you order: confirm your transmission code and casting/part numbers. Not sure? Message us through eBay with your VIN or transmission tag and we will confirm fitment the same business day. Rebuilder shops — ask about volume pricing. We stock transmission hard parts by family and can hold inventory for scheduled builds.