Wabco DEF Pressure Limiting Valve - 442 001 521 1 / S975-009-004-0

Orders are typically processed within 24–48 hours, Monday through Friday, excluding major U.S. holidays. Shipping options include Small Package Saver, Ground, Second Day Air, and Next Day Air. Free Shipping applies to qualifying items within the contiguous 48 states. Freight or oversized shipments require a commercial address. Please inspect all deliveries and report damages within 24–48 hours. We ship only within the continental U.S. and cannot deliver to P.O. boxes or international locations. Most orders ship from our North Carolina warehouse. For estimated transit times, see the shipping chart. Read more information.

Expert-selected truck parts

At FleetPro Parts, we specialize in supplying OEM replacement parts for heavy-duty trucks. From Freightliner and Detroit Diesel to Cummins, Mack, Volvo, and Wabco, our catalog covers the components you need to keep your fleet moving. Every part we stock is tested, reliable, and built to match OEM standards, so you can order with confidence. Our team knows truck parts inside out—from engine cooling and steering to AC systems, alternators, and fuel components. Whether you’re maintaining a single truck or managing an entire fleet, we make it easy to find the right part, at the right time. For when it matters. More about Us.

FleetPro Truck Center Inc • 4989 Hendersonville Rd, Fletcher, NC 28732 • Phone +1 888-722-1331