1994-1998- Dodge 5.9L Cummins PacBrake PRXB Exhaust Brake from PacBrake [C44072] 4" PRXB Exhaust Brake Kit with MAXIMUM EXHAUST FLOW DESIGN (Air Actuated) DirectMount Comes with Air Tank/Hose and Accessory Kit and Heavy Duty Exhaust Valve Springs. Diesel engines, unlike gasoline engines, don't slow down simply by taking your foot off the accelerator; they rely on service and supplemental brakes. An exhaust brake is a form of a supplemental brake, and they work much differently than their conventional counterparts. Introducing the Pacbrake PRXB Pacbrake’s flagship product, the PRXB (pressure regulated exhaust brake), is the unquestioned leader in the supplemental brake industry. The patented PRXB design delivers the strongest braking horsepower, greatest speed reductions and shortest stopping distances possible without the use of service brakes. It maintains optimum retarding performance by maximizing the exhaust backpressure throughout the entire RPM range. Unlike a typical exhaust brake, which requires high RPMs to work properly, the PRXB delivers constant exhaust pressure (braking) as early as 1200 RPM through to the maximum allowable RPM. ** Trucks with 4" aftermarket exhaust system with HX/HY35 turbo require an additional adapter C11342 - $40.00, select option on dropdown menu below. **Trucks equipped with an aftermarket turbo other than HX/HY35, contact Pure Diesel Power 715-254-1833 Select transmission option below. Automatic Transmission equipped trucks include a lockup controller and cost $300 additional.