PACCAR is the parent company of Peterbilt Motors and the manufacturer of the PACCAR MX engine family — including the MX-13 and MX-11 — that powers a large share of the current Peterbilt lineup. PACCAR genuine parts are engineered to OEM specifications for Peterbilt applications, covering engine components, filtration, exhaust aftertreatment, and chassis parts. Whether you're sourcing parts for a PACCAR MX-powered 579, 567, or 520, genuine PACCAR components ensure compatibility and meet the engineering standards the engine was designed around.