Peterbilt 389 Specs

Peterbilt 389

The new Peterbilt Model 389 combines a traditional cab design with aerodynamic enhancements for increased fuel savings. An optional fuel-efficiency package as well an optional day cab configuration provides application-specific versatility. The Model 389 is powered by the PACCAR MX-13 engine, designed for longer service intervals, increased uptime and lower operating costs that ultimately results in a higher resale value. In addition the Model 389 incorporates Peterbilt's all-aluminum lightweight cab designed to not only provide extreme durable, but allows for increased payloads to maximize performance and profitability.

We are independent dispatch company. We offer the dispatching services for owner operators.

About Truck 

This affordable truck is new for Peterbilt, representing all the work that had to go into re-engineering the frame and hood to cram the '07 engines and their associated cooling into the chassis. Both Peterbilt and sister Paccar company Kenworth have been very clever in re-doing their premiums for 2007, taking the opportunity to upgrade features, comfort and appearance to help offset the price increases that inevitably come from the 2007 engine technologies. So, while you're likely to pay more, you'll also be getting more. 

Most obvious on the 389 are cosmetic changes, many of which add to the aerodynamics and offset some past and potentially new fuel economy issues. The grille surround is now a one-piece unit that looks infinitely better than the old riveted pieces and has a smoother radius for better air flow. Headlamps are smoother and house much better-performing lighting sets that provide more than double the light output of the previous pods and give the bulbs a 60 percent improvement in durability. Directional signals are LEDs for virtually lifetime durability. 

Mirrors have been redesigned and hang on the cowl, a mounting borrowed from Kenworth, but a great idea nevertheless. They are more aerodynamic as well as offering better visibility. 

The 389 hoods are also different from the 379's – though not enough to upset Peterbilt purists. They are durable, lightweight and feature an anti-blow-down device. 

In addition to these standard features, there's an aero package that adds some subtle "tune-up" stuff, such as an air dam behind the front bumper and streamlined tool and battery boxes, some changes to the top fairing and an oval exhaust that can be worth 3/10 mpg. Considering it detracts not one whit from the traditional appearance, this Efficiency Package could be a wise investment. 

Under that impressive red hood sat an equally impressive red Cummins ISX. This one was rated 550 horsepower and 1,850 pounds-feet for hill-stomping performance with the best of civility and manners. 

The ISX is truly a tour de force, created to take over from the old N14 when emissions requirements got too much for it. So the ISX has all the building blocks to sail through emissions reductions called for in 2004, 2007 and 2010 – in fact, likely whatever comes in the 2014 timeframe. There were some issues with exhaust gas recirculation valves in early EGR ISXs, and it is worthy of note that the EGR valve has been relocated to the cool side of the engine for 2007. There are also a few subtle changes to the block that improve coolant flow. But the bigger changes include the electronic controls for the variable geometry Holset turbo, and the diesel particulate filter. 

Electronic control allows for closed-loop control of the VGT. Instead of the engine controller guessing what is needed, now the control circuit knows what the VGT has to do. The result is even better throttle response – a major plus that came from the VGT in the October '02 engines, and, likely, this time, an additional opportunity to address fuel economy. 

The diesel particulate filter is part and parcel with the engine as we go into 2007, and Peterbilt does a very elegant job of integrating this bulky component behind the passenger-side toolbox/step. The downside is, it reduces the size of the box. But from this engineer's perspective, it does increase the Wow factor of the 389. 

Up behind the big red motor was the dream-team 18-speed, a transmission every gearjammer should want. Refinements to the age-old Eaton Fuller double countershaft transmission make it a sweet-shifting and relatively quiet box that just seems right with a long-nose Pete. And the manual 18-speed is bulletproof. 

Axles under the truck were Eaton/Dana, which is no surprise, as these partners are the preferred Paccar drivetrain suppliers. The ratios in the rear ends were 3.70s, which were likely specified for performance rather than economy. The last ISX 550 I drove with 22.5-inch rubber had 3.55 ratios that work better in most applications. As they say in the ads, ask your dealer. 

Our company afford dispatch services to make your job as a truck driver much easier for you.

Operational Factors 

The engine manufacturers and the OEMs have gotten pretty savvy with daily checkpoints around the truck. Peterbilt has become very refined in the systems around the chassis that allow for electrical service and troubleshooting. And you have to be impressed by the long-established clutch lubrication points on the frame rail, left side. 

The databus dashes are an enormous leap forward in terms of the packaging of the wiring, the weight, and the diagnostics of the electrical system. The electronic backbone of the truck is second to no other in letting the dealer or the shop operator know what is happening with the vehicle. 

Meanwhile, a walkaround of the recent show at the American Trucking Associations convention revealed that the Volvo and Mack engines that use the same Holset turbo mount the electronics off the turbo, and also run engine coolant through the module.