Overview

Overview

This 2026 Peterbilt 579 is a conventional day cab with a Model Year 2026 engine, featuring an Aero 124 BBC aluminum cab and Metton hood with a Prestige interior in Sterling Gray. The truck is spec'd for general freight hauling with a van trailer application, sized for a 53 ft trailer with 12 ft trailer height, a 36" kingpin, and 2 trailer axles.

Engine & Drivetrain

Power comes from a Cummins X15 rated at 450 hp at 1700 rpm governed, with 1650 lb-ft of torque at 950 rpm, built to the 2024-emissions EFF series. It's paired with an Eaton EEO-16F112C12 Endurant automated 12-speed transmission with no cooler, running an RPL20 interaxle driveline and an RPL25 SD driveline with 1 midship bearing, on a 3.25 rear axle ratio. The truck includes a Jacobs compression brake, a PACCAR 160-amp brushed alternator, a PACCAR premium starter (X15-specific), and three PACCAR premium 12V dual-purpose batteries rated at 2190 CCA. Other engine equipment includes an immersion-type block heater (110–120V), an 18.7 CFM aspirated air compressor, a high-efficiency cooling system, a single RH SOC exhaust with DPF/SCR under the cab in a single module and a 36" chrome standpipe with clear coat, a predictive cruise control package, and a powertrain calibration optimized for balanced service with frequent start-and-stop cycles.

Chassis & Axles

The front axle is a Meritor MFS+12E rated at 12,500 lbs with a 3.5" drop, and the rear axle is a Meritor MT40-14X rated at 40,000 lbs. GVWR comes in at 52,000 lbs, with a GAWR front rating of 12,000 lbs and GAWR first and second intermediate ratings of 20,000 lbs each; front axle load is 12,000 lbs, rear axle load is 40,000 lbs, and GCW is rated at 80,000 lbs. The frame rides on a 185" wheelbase and uses 10-5/8" steel rails to 285" with 5/16" rail thickness and aluminum frame rail crossmembers. Braking is handled by Bendix ADB22X-LT disc brakes front and rear, backed by Bendix ESP electronic stability program with ATC, ABS 6S6M, and a tire pressure monitoring system.

Suspension

Up front, the truck rides on taper leaf springs with shocks rated at 12,000 lbs and Tenneco shocks on the steer axle. Out back is a PB low air leaf suspension rated at 40,000 lbs, 52" AS, in a lightweight configuration. The cab itself sits on a cab air suspension.

Cab & Interior

This is a day cab configuration (no sleeper) with a thermal insulation package. The driver's seat is a Peterbilt LX, premium level, air ride, high back, while the passenger seat is a Peterbilt ST, non-adjustable, non-air ride, high back, in vinyl; the interior also includes driver's armrests on both sides and a toolbox under the passenger seat with tow hook holders. Up front, drivers get a multi-function steering wheel with Peterbilt logo, audio, and cruise controls on a tilt/telescope adjustable steering column, a one-piece curved windshield, and a 1-piece fixed glass rear cab window, along with power door locks and power windows and a combo fresh air heater/air conditioner. The 15" digital cluster display covers engine oil temperature, air filter restriction pressure, brake application air pressure, suspension air pressure, engine hourmeter, engine manifold pressure (turbo boost), and engine percent torque. Outside, there's a stainless steel sunvisor, bright-finish aero rear-view mirrors that are motorized and heated with integrated convex glass, a look-down mirror over the passenger door, and rectangular hood mirrors in bright housing. For entertainment and connectivity, the truck includes a ConcertClass AM/FM/WB radio with 3.5mm aux input, a standard 2-speaker package, satellite radio, Bluetooth phone and audio, a USB port plus dual USB charging port, and a Cobra 29 CB radio. Rounding out the cab are Peterbilt electric wipers with intermittent feature, auto-reset circuit protection, a triangle reflector kit, and a fire extinguisher.

Body & Equipment

The fifth wheel is a Jost JSK37 top plate, inboard mounted with an 18" air slide only, LH release, 6.6"–7" height, and a Jost lightweight inboard slider set at the centerline of the bogie. Frame equipment includes a frame-mounted deck plate and access package on the RH side, an aero bumper in steel 3-piece bright finish, and Polyarmor black quarter fenders with the Peterbilt logo. Fuel and DEF are handled by a 26" aluminum 120-gallon fuel tank on the LH under cab with a non-slip step and fuel cooler, along with an LH BOC DEF tank in the HD 14-gallon size with a polished stainless steel cover. The battery box is an aluminum space-saver unit mounted RH BOC. Lighting includes composite fender-mounted headlights with integral DRL/park/turn/side marker, five aero LED marker lights, daytime running lights, LED stop/turn/tail/backup lights bracket-mounted LH/RH at the end of frame, and two LED load lights flush-mounted low inboard BOC/BOS. The truck also comes equipped with global telematics hardware and wiring provisions for ELD telematics (RP1226, 9-pin diagnostic connector), a Bendix AD-HF air dryer with heater and coalescing filter, steel painted air tanks, gladhands/plug/ISO holder mounted BOC/BOS, and 12' AE lines, straight, with two 7-way plugs. The paint is Axalta two-stage, with a White cab, hood top, fender, and cab roof over a Black frame.

Tires & Wheels

Front tires are Yokohama 16-ply 295/75R22.5 RY023, while the rear set (eight tires total) is Yokohama 16-ply 295/75R22.5 TY517 MC2. Wheels front and rear are Accuride 43644SP 22.5x8.25 aluminum in standard polish, with eight rear rims.

Warranty & Protection

This unit carries a base emissions warranty on the Cummins engine of 5 years / 100,000 miles, Peterbilt's Class 8 standard coverage of 1 year / 100,000 miles (160,000 km), and a 5-year SmartLinQ Remote Diagnostics subscription.