The Alliant Power AP63404 is a new back pressure tube for 1999–2003 Ford 7.3L Powerstroke applications.

Features & Benefits

• New Alliant Power Back Pressure Tube (Alliant P/N AP63404)
• Fit, form, and function tested to meet or exceed original-equipment standards (per Alliant Power)
• Direct replacement for 1C3Z-9D477-AA / 1C3Z9D477 / 18378785
• Backed by Alliant Power’s 24-month, unlimited-mileage warranty

Application

• Ford E-350 Super Duty / F-250 Super Duty / F-350 Super Duty / F-450 Super Duty / F-550 Super Duty (1999–2003)
• Ford E-350 Econoline Club Wagon / E-450 Econoline Super Duty (1999–2002)
• Ford F-650 / F-750 / Excursion (2000–2003)
• Ford E-550 Econoline Super Duty (2002)
• Ford E-350 Club Wagon / E-450 Super Duty / E-550 Super Duty (2003)
• Alliant Power lists additional vehicle applications for this part number

Always verify fitment against your VIN, engine, and OE part number before ordering.

Cross-Reference / Replaces

• Ford: 1C3Z9D477, 1C3Z-9D477-AA
• Navistar: 18378785
• Alliant Power: AP63404

Warranty: Alliant Power’s standard warranty: 24 months with unlimited miles/hours on installed parts (Alliant Power warranty policy, rev. Aug 2025).