Direct Mount 4 inch PRXB High Performance Exhaust Brake Kit

Features

• 4" PRXB (Pressure Regulated Exhaust Brake) – delivers 50% more braking power at lower RPMs (1400–1800 RPM range)

• Direct-mount system – no restrictive backpressure when deactivated

• Includes onboard air kit: HP325 compressor, 0.5-gal tank, 25-ft coiled hose, air accessories, and fittings

• Patented 90° non-contacting butterfly valve – maximizes backpressure without seizing

• Built from hard anodized aluminum and stainless steel with Arcor nitride coating for durability and corrosion resistance

• Maintenance-friendly design – no gaskets required; easy upkeep with Pacbrake Superlube

• Includes transmission controller (for 48RE automatic)

• Designed for vehicles built from Jan 5, 2004, to June 27, 2005

Powerful, Precise, and Proven Exhaust Braking

The PacBrake C44033 PRXB Exhaust Brake Kit is the ultimate upgrade for 2004.5–2005 Dodge RAM 2500/3500 5.9L Cummins trucks equipped with the 48RE automatic transmission. Unlike standard exhaust brakes that rely solely on backpressure at high RPMs, the PRXB delivers superior braking power at cruising RPMs (1400–1800)—where you actually drive.

With its spring-controlled, pressure-regulated mechanism, the PRXB offers smooth, controlled deceleration and enhanced safety during towing or downhill braking. When deactivated, the exhaust flow is fully open—so it won't impact performance or fuel economy.

Built for reliability, the unit features precision-machined surfaces, eliminating the need for gaskets, and a non-contacting butterfly valve that prevents sticking or seizing. The Arcor-treated internals enhance wear resistance, corrosion protection, and overall lifespan, even in extreme diesel operating conditions.

This complete kit comes with everything needed for installation, including a high-output air compressor, coiled air line, controller, and fittings—making it ideal for applications with or without an existing onboard air system.

Fitment:
2004.5, 2005 Dodge RAM 2500/3500 5.9L Cummins ISB 24V

• Fits trucks built between Jan 5, 2004 – June 27, 2005

• For use with 48RE automatic transmission only

Specifications:

• Mount Type: Direct

• Valve Type: 24-Valve

• Size: 4.0"

• Compressor: HP325 Series

• Tank Capacity: 0.5 Gallon

• Air Hose: 25-foot coiled

• Air Actuation: For vehicles with or without existing onboard air

• Transmission Controller: Included

Warranty:
Backed by Pacbrake's Limited Warranty (see manufacturer for full details)

Emissions Compliance:
This product is a supplemental braking device and is legal in all 50 states when used according to manufacturer guidelines.