Peterbilt 579

The 579 is Peterbilt’s on-highway tractor, which Peterbilt lists as a Class 8 truck and calls its “on-highway flagship”; the US weight classes are explained in GVWR, GCWR and GAWR. Peterbilt, a PACCAR company, names the truck the Model 579 and dates it to 2012; the current version was unveiled on 3 February 2021 as the “new Model 579”. The battery-electric 579EV was introduced in 2020, and Peterbilt introduced a next-generation 579EV on 28 April 2025.

Overview and generations

Peterbilt’s company timeline lists “2012: Model 579 Hits the Highway”, describing the 579 as the “Class of the Highway Market”, and “2018: The Model 579 Gets Ultra Comfy with UltraLoft”, a new high-roof sleeper. Peterbilt’s Heavy Duty Body Builder Manual of May 2017 drew the 579 of that time in two versions, the 579-123 and the 579-117, with bumper-to-back-of-cab dimensions of 123.5 and 117.6 inches, and listed 44-, 58-, 72- and 80-inch sleepers for it.

Peterbilt launched the current version with three releases dated 3 February 2021. Peterbilt describes it as “thoroughly redesigned” and “this major evolution of the Model 579”, with a new sloped hood, optimised aero components, the 2021 PACCAR MX-13 and MX-11 engines and the PACCAR transmission, a cab and sleeper it calls 10% quieter, a 15-inch digital display, and driver-assistance systems including collision mitigation, lane departure warning and the new lane keeping assist. Peterbilt says it worked with over 50 customers on the design, that validation units had accumulated 1.5 million real-world miles, and that over 1,000 hours of computational fluid dynamics analysis and over 7.8 million CPU processing hours went into evaluating the exterior design, research it credits with a 7% improvement in fuel economy. The truck was available for order from that day as a day cab, with the integral 80-inch UltraLoft sleeper and with other sleeper sizes. Peterbilt’s release of 7 June 2021 reports the delivery of the first production new Model 579, to Smith Transport of Roaring Spring, Pennsylvania, and says the truck was then in full production; the same release dates the launch of the UltraLoft to 2018.

Peterbilt’s present 579 page lists the truck as Class 8 and on-highway, with up to 605 hp and up to 2,050 lb-ft, front axles of 12,000 to 14,600 lb, rear axles and suspensions of 21,000 to 46,000 lb with lift axles available, and sleepers of 44 to 80 inches. Peterbilt says the 750,000th truck assembled at its Denton, Texas, plant was a Model 579, handed to TMC Transportation on 14 November 2023. Peterbilt’s FAQ says its trucks are built primarily in Denton for the US market, that its production in Canada is centred at Sainte-Thérèse, Quebec, and that its Mexicali, Mexico, plant “also contributes to manufacturing”; its release of 16 April 2026 says the Quebec plant builds trucks exclusively for the Canadian market. In a release of 5 January 2022 Peterbilt said it would show at CES the first Model 579 equipped with the Aurora Driver, which it describes as “a Level 4 advanced autonomous system”, and that Aurora had added the new Model 579 to its heavy-duty test fleet.

Cab

Peterbilt’s launch release lists a redesigned, stronger Metton hood that is narrower and more resistant to damage, the aerodynamic “bird” ornament, a bright stainless steel grille, halogen headlights or optional LED headlights, a new three-piece bumper that integrates the forward radar cover and a larger air dam, revised mirrors, fairings, side skirts and closeouts, and a revised A-pillar vane that redirects air around the windshield. The current 579 page offers two Metton hoods, with bumper-to-back-of-cab dimensions of 118 and 124 inches; bumpers in molded-in colour, molded and painted, chrome-plated steel or painted steel; LED headlamps with a built-in heater; an optional LED light system combining fog, driving and cornering lights; standard aero or advanced aero mirrors; tip-out chassis fairings that open without tools; and two aerodynamic packages. EPIQ includes the bumper air dam, bumper-to-hood seals, wheel-well closeouts, A-pillar fairings, chassis fairings, under-cab closeouts, under-fairing skirts, extenders and rubber flares; EPIQ MAX adds the advanced aero mirrors, rear tandem fairings and wheel covers. The 2021 brochure says the LED headlights use half the power of halogen headlights and carry infrared heating elements for lens defrost, and that the driving light doubles the high-beam output.

The manual gives heights from the bottom of the frame rail: 83.7 inches to the top of the standard cab roof of the 579; for the overall cab height it adds half the sum of the front and rear frame heights and tyre dimensions. The 579 page lists 44-, 58- and 72-inch sleepers, an 80-inch “Discrete” sleeper and the 80-inch UltraLoft. The manual’s sleeper table, which it gives for the 579 and 567 together, covers the separate (“discrete/detachable”) sleepers:

The UltraLoft is an integral 80-inch sleeper with 8 feet of headroom and 70 cubic feet of storage. Peterbilt says it carries the largest mattresses in the industry and takes a TV of up to 32 inches and a microwave of 1.1 cubic feet; in the double-bunk version a ladder folds away when not in use. Peterbilt lists sound abatement, an independent HVAC system with separate controls, an optional fuel-fired heater and several no-idle hoteling options in the sleeper. How sleeper and day cabs differ in general is covered in truck cabs explained.

Inside, the 579 page lists three trim levels, Prestige and Premier in Sterling Gray and Platinum in Sterling Gray or Saddle Tan, with dark dash and door-pad uppers; a 15-inch digital display; up to two USB ports and two 12-volt ports; two fixed cup holders; storage bins in the B or C panel; carpet or rubber floors; and Peterbilt LX, ST and HP driver seats, a Peterbilt ST passenger seat, Sears Atlas seats, a two-person passenger seat and a RollTek driver seat. The steering wheel carries audio, phone and cruise controls, and Peterbilt names a crank-mounted fan, an engine-mounted air cleaner and acoustically tuned engine mounts among the engine changes it says improve the driving experience. Peterbilt’s release of 3 February 2021 describes the display’s three views: a minimised view with only the speedometer and tachometer, a basic view with air and oil pressure, fuel and DEF levels and water temperature, and an enhanced view with the most gauges, chosen from over 30 information sources; before departure it can run a systems check of 13 systems. From September 2024 Peterbilt offered a new infotainment centre, optional in all its conventional models, with wired and wireless Apple CarPlay, wireless connectivity for Android devices, AM/FM/Weather/SXM radio, support for four analog HD cameras with split-screen viewing, truck-specific navigation with map updates at no cost for three years, and English, Spanish and French. The brochure says the SmartLINQ remote diagnostics system is standard on every new Model 579 and monitors more than 900 engine and emissions parameters.

Engines

The 579 page lists six engines, all inline six-cylinder units:

PACCAR’s 2024 sheet gives the MX-13 a 130 mm bore and 162 mm stroke, a displacement of 12.9 litres, a dry weight of 2,500 lb, an oil system capacity of 42 US quarts, a governed speed of 2,100 rpm, EPA 2024 certification and a maximum operating weight of 140,000 lb, with oil-change intervals of up to 75,000 miles; PACCAR claims up to 450 lb less weight than 15-litre engines. Peterbilt’s 2021 brochure gives a stroke of 160 mm and a governed speed of 2,200 rpm for the MX-13, and a B10 design life of 1.0 million miles. The MX-11 is a 10.8-litre inline six with a 123 mm bore and 152 mm stroke, a dry weight of 2,200 lb, 39 US quarts of oil and a governed speed of 2,100 rpm on PACCAR’s 2024 sheet (2,200 rpm in the brochure), rated at 355 hp with 1,250 lb-ft, 375 hp with 1,350, 400 hp with 1,450, 415 hp with 1,550, 430 hp with 1,650 (or 1,450/1,650 as a multi-torque rating) and 445 hp with 1,700 lb-ft, all at 900 rpm, for a maximum operating weight of 110,000 lb; PACCAR says it weighs 300 lb less than a 13-litre engine. Peterbilt’s timeline dates the MX-13 to 2010 and the MX-11 to 2015. No Peterbilt or PACCAR document opened gives kilowatt or newton-metre figures for these engines. The same PACCAR engines are described on the Kenworth T680 page. A PACCAR release of 7 July 2026 says Peterbilt trucks with MX-11 and MX-13 engines receive updated software on diesel exhaust fluid (DEF) inducements, raising the final inducement speed limit from 5 to 25 mph and extending the time before it is reached from 4 to 160 hours for component-related or fluid-quality issues; trucks manufactured after 20 July 2026 have the software installed at the factory. How SCR and DEF work is explained in SCR and AdBlue.

On 4 June 2024 Peterbilt made a low-NOx version of the MX-13 that meets the California Air Resources Board’s (CARB) Omnibus Regulation available in the 579, 567 and 589. Peterbilt describes a larger aftertreatment system with a compact twin assembly, a 48-volt generator in the flywheel housing and an electric heater at the inlet, a larger mixer and a longer SCR catalyst, and two ratings: 510 hp with 1,850 lb-ft, and 455 hp with 1,650 lb-ft “between 900 and 1,325 RPM”. PACCAR’s CARB 2024 sheet adds a dry weight of 3,100 lb, an aftertreatment weight of 412 lb, a governed speed of 2,200 rpm and a maximum GVWR of 140,000 lb, and notes that engine, aftertreatment and supporting components weigh 1,100 lb more than the EPA 2024 version.

For natural gas, Peterbilt made the Cummins X15N available on the 579, 567 and 520 on 26 March 2024, with orders scheduled for production in the third quarter of 2024, at up to 500 hp and 1,850 lb-ft; Peterbilt says the engine is designed to meet the 2024 and 2027 EPA and CARB regulations. Peterbilt’s release for ACT Expo in May 2024 lists a 579 UltraLoft with the X15N among its exhibits, and its release for Truck World in Mississauga in April 2026 lists a “Model 579 CNG” with the X15N for the show’s Ride & Drive event.

Transmission

The 579 page lists six gearbox families: the PACCAR TX-12 12-speed automated (“On-Highway Fuel Efficiency”), the PACCAR TX-18 18-speed automated (“Vocational, Heavy Haul, High Performance”), the Endurant HD 12-speed and Endurant XD 18-speed automated gearboxes, Eaton FR and RT manual gearboxes with 9, 10, 11, 13, 15 or 18 speeds, and Eaton UltraShift Plus automated gearboxes with 10, 11, 13 or 18 speeds. Peterbilt’s timeline dates “the PACCAR 12-speed automatic transmission” to 2017. PACCAR’s 2025 sheet gives the TX-12 12 forward and 2 reverse gears, a torque capacity of 1,850 lb-ft, a lower cruise speed limit of 1,100 rpm, 16 pints of oil with an oil-change interval of 750,000 miles, a system weight of 657 lb, a maximum operating weight of 110,000 lb and an 8-bolt bottom power take-off rated at 95 hp.

Peterbilt added the PACCAR TX-18 and TX-18 Pro on 15 February 2022 for the 567, 389 and 579 with MX engines. They work only with the MX-11 and MX-13, take up to 1,850 lb-ft and are rated up to 140,000 lb GCWR; Peterbilt lists a high-pressure diecast aluminium case, helical gearing, an extreme-duty clutch, four application-specific calibrations, two power take-off openings with a combined 160 hp, up to six configurable reverse speeds on the TX-18 Pro, and a stalk-mounted shifter with Drive, Neutral, Reverse and Manual modes. On 14 June 2023 Peterbilt added an Off-Road Calibration as a secondary mode and made Rock-Free Mode standard on the TX-18 PRO. PACCAR’s 2025 sheet gives 18 forward and one to six reverse gears, a maximum of 510 hp, 25.4 pints of oil, system weights of 808 lb (TX-18) and 813 lb (TX-18 PRO), ratios from 14.32 in first to 0.7 in eighteenth with an overall spread of 20.46, and maintenance intervals of 500,000 miles or 5 years on-highway and 250,000 miles or 3 years in vocational use.

On 24 March 2025 Peterbilt made the PACCAR TX-12 PRO available with the MX-13 in the 579, 567 and 589, for on- and off-highway work such as dump trucks and tankers, supporting up to 1,700 lb-ft with the MX-13. The 579 page describes the TX-12 PRO as engineered for engines of up to 1,000 lb-ft and a maximum GCWR of 70,000 lb, with dual power take-off, an extreme-duty clutch, Rock Free Mode, an off-highway calibration and a secondary configuration; the two documents give different torque limits. Peterbilt and PACCAR call these gearboxes automated transmissions; automated gearboxes in general are covered in automated manual transmissions.

Axles, suspension and brakes

The 579 page lists front axles of 12,000 to 14,600 lb from Dana, Hendrickson and Meritor on Peterbilt Front Air Leaf, Hendrickson Softek or taper-leaf springs, and rear axles from PACCAR, Dana and Meritor on the Peterbilt Flex Air, Low Air Leaf, Low-Low Air Leaf, Air Leaf and Air Trac suspensions, the Hendrickson HMX EX, the Neway ADZ or Reyco suspensions. Among the fleet specification options for the 579 UltraLoft, Peterbilt lists the PACCAR powertrain with the MX engine, the TX-12 and the DX-40 axle. PACCAR’s DX-40 sheet gives this tandem axle a gross axle weight rating of 40,000 lb and a gross combination weight of 80,000 lb, with ratios from 2.47 to 3.70 and torque ratings of 1,650 lb-ft straight and 1,850 lb-ft multi-torque; it lists a pinion thru-shaft design, a driver-controlled forward-axle differential lock and up to 150 lb of weight saving. Peterbilt’s timeline dates the 40,000-lb PACCAR tandem axle to 2016. What an axle ratio does is explained in axle ratios and final drive. No Peterbilt document opened prints a list of wheel formulas for the diesel 579.

On 10 December 2025 Peterbilt made the Bendix Intellipark electronic parking brake available on its Class 8 and medium-duty trucks, with rollaway mitigation, which applies the parking brakes on truck and trailer if the driver leaves the cab without setting them, automatic release of the trailer brakes when the tractor moves, and Smart Unpark, which uses interlocks on door position, seat belt and vehicle movement. Peterbilt’s release of 26 October 2025 gave the electronic park brake on the 579 UltraLoft as available from the fourth quarter of 2025.

Fuel and DEF tanks

The Heavy Duty Body Builder Manual, which covers the 589, 579 and 567 together, lists 20-inch, 23-inch and 26-inch fuel tanks, with useable capacities from 40 to 150 US gallons (46 to 163 gallons total): the 20-inch tanks up to 80 gallons useable, the 23-inch tanks up to 120 and the 26-inch tanks from 50 to 150. Its DEF tanks hold 10.2, 16.1 or 20.1 gallons, and the aero versions 13.9 or 17.9 gallons. No document opened gives a kerb weight or a gross vehicle or combination weight rating for the diesel 579.

Safety and driver-assistance systems

The 2021 brochure describes the camera and radar system of the new Model 579, with overspeed alerts, collision mitigation, lane departure warning, highway departure braking, side object detection for the passenger-side blind spot, and lane keeping assist, which uses an electric motor mounted on the steering column; the collision mitigation can reduce the truck’s speed by up to 50 mph (80 km/h) and then resume the set speed. The present 579 page lists lane keeping assist, adaptive cruise control, automatic emergency braking with enhanced collision mitigation, lane departure warning, highway departure braking and side object detection, and adds pedestrian detection, automatic high beams and automatic wiper control.

On 12 December 2023 Peterbilt announced enhanced standard collision mitigation features on the 579 with the Bendix Fusion system, led by the Fusion Stop and Auto-Go function, which can brake the truck to zero mph in heavy traffic, holds it after an automatic braking event and then resumes the pre-set cruise speed; Peterbilt also names highway lane departure braking, multi-lane emergency braking and stationary vehicle braking. On 10 March 2025 Peterbilt made Bendix Fusion Stop and Auto-Go Advanced available on the 579, with a new forward-facing camera and upgraded software adding pedestrian automatic emergency braking and High Beam Assist, available with the MX-11 or MX-13 and the TX-12, or with the Cummins X15 and the Eaton Endurant 12-speed.

Peterbilt’s Digital Vision System-Mirrors, introduced on 25 April 2024 for the 579 and 567, use one high-dynamic-range camera in the driver-side mirror head and two in the passenger-side head, with hydrophobic lenses, shown on monitors of 12.3 inches (driver side) and 15 inches (passenger side) on the A-pillars, in traditional, panoramic or expanded layouts; they offer automatic trailer tracking and panning, infrared night vision and an automatic camera defrost below 43°F, and Peterbilt claims “a fuel savings of up to 1.5%” from the smaller mirror heads.

Battery-electric 579EV

Peterbilt’s timeline lists the introduction of the battery-electric 579EV in 2020, for short-haul and drayage work in port operations. Peterbilt’s releases of 2021 and 2022 give it a range of up to 150 miles and a recharge in three to four hours on a DC fast charger. In January 2021 Peterbilt reported that a 579EV had reached the summit of Pikes Peak, at 14,115 feet, on a road with an average grade of 7% and 156 turns over the last 12.42 miles, recharging on the descent by regenerative braking. Peterbilt reported an order for five 579EVs from Sunbelt Rentals in July 2021, the delivery of ten 579EVs to Shippers Transport Express for drayage at the Port of Oakland in August 2021, with five more to follow at the Port of Long Beach, and two to Quantix in August 2022; on 29 May 2024 it announced an order for 150 Model 579EVs from Einride, its largest electric vehicle order to date. Peterbilt’s 579 battery-electric body builder supplement of September 2022 gives wheelbases of 190 and 216 inches, the longer one available with an electric power take-off, and says the truck uses the pre-VMUX electrical architecture. Peterbilt’s 579EV operator manual (April 2025) describes eAxles, each with its own propulsion motor and inverter and an integrated 2-speed or 3-speed transmission, DC charging at up to 150 kW, an optional 19.2 kW AC charger and a CCS1 charge port on the driver’s side; the quick start guide of September 2023 gives a maximum vehicle charge speed of 150 kW.

On 28 April 2025 Peterbilt introduced the next-generation 579EV, “building on the diesel-powered Model 579 platform”, for regional haul and drayage. The release describes the PACCAR ePowertrain, with a midship-mounted eMotor containing two electric motors and an integrated 3-speed transmission, up to 605 hp and 1,850 lb-ft, lithium iron phosphate batteries, three-stage selectable regenerative braking and support for any wheelbase of 190 inches or longer and gross combined weights up to 82,000 lb. Peterbilt lists three battery capacities with a maximum range of 200 miles, DC charging at up to 350 kW for an 80% charge in just over 90 minutes, an electronic parking brake, Bendix Fusion Stop and Auto-Go Advanced as standard, an EV-specific grille with splayed bars and blue accents, a Platinum Ionic Gray interior and the 13-inch SmartDisplay touchscreen.

Peterbilt’s 579EV sales sheet of April 2025 lists three peak power options, 470, 540 and 605 hp, each with 1,850 lb-ft, and, in a separate list, three usable battery capacities of 250, 375 and 500 kWh, as well as factory-installed lift axles. Peterbilt’s 579EV page gives a GCWR of 82,000 lb, a 14,600 lb front axle, rear axles of 38,000 to 46,000 lb, a range of 100 to 200 miles, an 80% charge in about 90 minutes and electric power take-off provisions of 25 and 150 kW; Peterbilt’s blog of 28 April 2025 gives a charge to 80% “in 2 hours or less with all battery capacities” for the 579EV and 567EV and calls both “available today”. The operator manual of December 2025 for the 567EV and 579EV says each high-voltage battery string holds two battery packs and a relay box in series and supplies 650 V, with a capacity of 228 Ah and a nominal energy of 141 kWh; the difference between installed and usable energy is explained in installed vs usable battery capacity. The battery-electric body builder manual of September 2025, whose dimension section covers the 579EV and 567EV, gives its 579-118 drawing a bumper-to-front-axle dimension of 49.9 inches. Lower down, the same 579EV page lists a tandem e-axle powertrain with combined ratings of 670 hp (500 kW) peak and 536 hp (400 kW) continuous, 40,000 lb Meritor tandem e-axles, 400 kWh of total capacity at 650 volts, charging at up to 150 kW (three hours at Level 3) and an optional 19.2 kW AC charger (18.5 hours at Level 2), a 117-inch BBC SMC hood and HID xenon or halogen headlights; the two parts of the page describe different powertrains. Peterbilt’s release of 26 October 2025 lists a “Next-Evolution Model 579EV” on its stand at the ATA show in San Diego; no document opened reports a delivery of the next-generation 579EV.

Peterbilt’s ACT Expo release of May 2024 also lists a “Toyota fuel cell module for Peterbilt Model 579 HFC” among its exhibits, as a zero-emissions solution for extended-range regional haul; no document opened gives figures for it or reports its production.

Source notes

Engines, in the maker’s units: PACCAR MX-13, 12.9 l, 405-510 hp and 1,550-1,850 lb-ft (EPA 2024 on PACCAR’s sheet); PACCAR MX-11, 10.8 l, 355-445 hp and 1,250-1,700 lb-ft; CARB MX-13 at 455 hp and 1,650 lb-ft or 510 hp and 1,850 lb-ft; Cummins X15, 15 l, up to 605 hp and 2,050 lb-ft; Cummins X15N natural gas, 14.5 l, up to 500 hp and 1,850 lb-ft; Cummins ISX12N, 11.9 l, up to 400 hp; Cummins L9N, 8.9 l, 320 hp. Gearboxes: PACCAR TX-12, 12 forward and 2 reverse, 1,850 lb-ft; PACCAR TX-18 and TX-18 PRO, 18 forward, to 1,850 lb-ft and 140,000 lb GCWR; Endurant HD and XD; Eaton manual and UltraShift Plus. Rear axle: PACCAR DX-40 tandem, GAWR 40,000 lb, GCW 80,000 lb, ratios 2.47-3.70. Axle ratings on Peterbilt’s page: front 12,000-14,600 lb, rear 21,000-46,000 lb. Cab: hoods with bumper-to-back-of-cab dimensions of 124 and 118 in and 44-, 58-, 72- and 80-inch sleepers (Body Builder Manual, September 2025); day cab and the 80-inch UltraLoft integral sleeper. Fuel tanks of 40 to 150 US gallons useable. No document opened gives a kerb weight or a gross weight rating for the diesel 579.