Peterbilt 387/Cummins ISX long term test

Peterbilt 387 tractor

My new Cummins truck isn’t a Dodge Ram. My new Cummins is the Ram’s daddy, a Cummins ISX 445, displacing 15 liters, with dual overhead cams and a variable geometry turbo. The turbo is huge, and the valve cover is half the size of the redhead’s kitchen table.

Variable geometry started as “variable nozzle technology” with the Chrysler Turbo IV setup. It lets the turbocharger act small at lower rpm, and large at higher rpm, so it has fast spool-up with high efficiency and high capacity.

Peterbilt 387 class 8 truck review

The engine tag says it has 445 hp at 2,100 rpm, but mine seems to flat line at around 1600 rpm. The tag also mentions torque, and based on how it does the hills, I’m guessing it’s pretty close to the 1,700 foot-pounds it advertises, at 1,200 rpm.

I couldn’t believe that number was for real at first, but my first load took me across US 60 and down US 63 from Springfield to Memphis, up and down the hills over the mountains and through the valleys, and this engine took climbs in high gear that used to require two or three downshifts in my last truck. US 63 in Arkansas used to require a break every hour or so because your right arm got worn out from the constant shifting, but now I downshift more for small towns and curves than I do for hills.

cummins diesel engine

There are things with the new engine that take a bit of getting used to. One is the incredible torque, coming in low on the tach. I’m used to the torque band starting around 1,200 or 1,300, and topping out around 1,700 or so. This thing tops out around 1,500, but it keeps on digging below 1,000 rpm. I know Jeepers who are jealous.

Cummins credits its low end torque to the variable geometry turbo, which is also responsible for another thing that I’m certainly not used to in a big diesel, the absence of turbo lag. When you mash the go pedal, you get results right now! Immediately! With no messing around at all! This makes for a touchy throttle, but I can live with that. (I could live with 1,700 ft-lbs even if they painted it pink with lavender heartbeat stripes.)

Equally good as the power is the engine brake. I’ve used the famous Jake brake on quite a few different engines, with results varying by the engine. On some of them the engine brake makes a pleasant noise while operating but does little else; others work well at holding back a load on a hill.

Cummins ISX diesel engine

On this ISX, the Jacobs engine brake flat puts the rest to shame. You don’t want to use it with an empty trailer, it’s just too much. Down a big hill, you can get by with the low setting if you’re in the higher gears, but not at all in the lower gears. Loaded is where it shines, on a 9% grade with a gross weight of 73,500 lbs, it held the speed at 35 mph in 9th gear. In my last truck with the Series 60 Detroit, that weight on that grade required 6th gear and about 20 mph to hold it back.

With that much torque, the truck gets hungry in the hills when you use it; but out in the flat land, fuel economy is actually increased.

The new Cummins meets the new California emissions standards, and the truck has a pretty prismatic sticker on the door to prove it. There’s a minor irritation and a major complaint with that. The minor irritation is the DPF, a big can under the truck that has a ceramic element to trap the soot in the exhaust. When the DPF gets full, the turbo does something to heat the exhaust up pretty close to 2,000° to convert the soot to carbon dioxide. That heat can cause some problems in some places, so there is an override switch so you can shut the system off if you are going into a building, or driving under trees, in a grass field, parking on asphalt, or any other situation where it could start a fire. The driver has to remember to turn it off in those situations, and then remember to turn it back on again when the fire danger isn’t so high, or else the DPF gets full and you have a very expensive repair, not covered by warranty.

Cummins ISX diesel

To meet the California emissions and get the pretty prismatic sticker on the door, the truck also has to be programmed so that it won’t idle more than five minutes. Big trucks have auxiliary power units (APUs) to keep the interior comfy and let the fridge and TV work without the engine on. Wonderful plan, but what about when the APU fails and it’s 7° and the driver has to take his ten hour break (yes, I’ve already had it happen — twice!)? How tired is that trucker going to be when he has to spend his entire 10 hour break restarting the truck every 5 minutes just to stay warm? Parents Against Tired Truckers had success getting the national DOT to make the hours of service worse than they had been; maybe they can help truckers out with the EPA. If they would, I’d even quit wearing my Truckers Against Pissed Parents hat. (P.A.T.T. should have asked the truckers what changes to the hours of service regulations would help eliminate trucker fatigue.)

The Peterbilt 387

On November 26 2010, I took possession of a galaxy-blue 2009 Peterbilt 387; the previous leaser only put 65,000 miles on it, not much for an over the road truck. It still looks and smells new, and has most of the 500,000 mile/5 year warranty left.

I never really wanted a Peterbilt, they build a really good truck, but it’s kind of like a Harley. There’s an image thing that seems to draw a lot the kind of people that I don’t care for. I also really never thought I’d like a 387, as it’s based on the KW T2000. Trucker slang for the T2000 is “T too ugly”, and I think that’s a well deserved nickname, but I have to admit that the Pete designers toned the ugly down a bunch to the level of “just a bit odd.”

Now that I have a Peterbilt, I guess I’m going to have to quit telling the joke about the difference between a Peterbilt and a porcupine. I would tell some Freightliner jokes, but I don’t think there are any. I’m not sure if the reason is that the truck they build is the Freightliner joke, or maybe it’s just because getting stuck in one isn’t a laughing matter.

Peterbilt 387 class 8 truck

The 387 isn’t like the Petes of old; while it has a real wide cab like a cabover, it also has a hood. I thought visibility out of the cab would be compromised by its width, but the Pete designers did an excellent job of designing the mirrors to cover most of the blind spots.

The designers did a good job in the suspension, too. The ride is incredible, but great ride is one of the Peterbilt hallmarks. My last truck was a Freightliner Century, and I had a fancy computer stand that secured to the right seat; I had to secure the computer to the stand to keep it from jumping out on rough roads, and the ride was so rough that I had to replace laptops every couple years and rebuild the stand frequently. In this truck, the computer sits on a pair of milk crates stacked up between the seats, rough roads don’t even move it around.

The interior is nice and spacious, but it’s a bit shy of storage space. The model 379 Petes were really well designed in storage, for having such a tiny cab and sleeper they made excellent use of every square inch of available space. The 387 has a huge cab and sleeper, but doesn’t seem to have as much storage as the 379, or (as much as I hate to admit it) the Freightliner Century.

Peterbilt cab

Interior construction and materials are classic Peterbilt class. The plastic is nice looking, solid with an expensive feel. The dash is full of pretty chrome ringed gauges and nice looking switches, all in a good position for visibility and accessibility. Actually a bit too visible at night, I wish the dash lights would dim a bit more. The lowest setting is a bit too bright, but I can live with it.

The seating position is excellent; it actually fits the range of sizes real people come in. It’s really nice to be able to reach all the controls comfortably without having to have the seat so far forward that my knees are in the steering column. The seat is a lot higher off the ground than other trucks I’ve driven, that probably helps with the outside visibility but it does make the 13’9” overpasses that are common on the east coast a bit spooky, it looks like they are eye level when you are approaching them.

One thing that concerned me a bit was that the mirrors are viewed through the wing windows, and the wing windows are solid mounted and don’t open. Opening a wing window to see a mirror is a quick and dirty trick when the window is fogged up or covered with grime from driving on a bad road, but the defroster keeps the inside of the window clear in even the worst winter weather, and the aerodynamics of the truck keep most of the road crud off the windows.

The downside is, it has the typical “aerodynamic whistle” at road speeds and the windows are down. The heater is excellent, at near zero temperatures you don’t even need it on high. Air conditioning is good too.

The new truck has a Rigmaster auxiliary power unit on it; it’s a 2006 model, and has been out to service more than it’s been operational. Rigmaster has gone bankrupt and finding parts on the road is a problem. Other drivers told me Rigmasters were troublesome even when new.

Peterbilt 387 dashboard

Outside of the engine, my favorite thing about this truck is the galaxy blue paint. It’s just a bit lighter than the 1970s Plymouth B5 blue, an incredible color in bright sunlight, and good in any lighting. The body design is actually quite nice in spite of the big odd shaped grille, and the truck actually looks longer than it is.

Due to the high windshield curvature, the wipers tend to freeze up pretty bad, and they leave a big unwiped spot in the middle when they do. As a big one piece glass, I’m sure it’s going to be a pretty penny to replace when it gets chipped up.

Probably the biggest drawback to the truck is the weight. With my last truck I could legally scale 49,500 lbs if I had one of our lightweight Reitnouer MaxMiser trailers; this new Pete will only allow a bit over 48,000 lbs of payload. Considering some of our loads pay by the pound, that is apt to hurt the income a bit. Fuel economy will make up for a lot of that, though, and if the maintenance costs are as low as I’m told they should be, I might come out ahead of the game.

That’s the good and the bad, now for the stupid, starting with the QualComm satellite communication unit; it has a touch screen and is supposed to have the feel of Windows so “it will be easier for a driver to use,” and it talks to you so you don’t have to look at it. Whoever thought a touch screen would be a good idea in a flatbedder’s truck really needs to get out of the office and see what we do for a living. Visibility in some parts of the screen is already a little hazy. The programming does kind of look and feel a bit like Windows…version 3.

truck tractor

The biggest problem is the talking. The feminine voice is supposed to be soothing, but sounds just like one of my ex-girlfriends at the wrong time of the month. QualCom charges by the character, so we use a lot of abbreviations, and it does poorly translating these abbreviations, so most of the time what it’s saying doesn’t make any sense and you have to look at the screen.

I really hate the nanny systems.

Keep an eye out, if you see me out there, give a wave. I’m not even real picky about how many fingers you use when you wave, although all 5 would be a bit nicer than just the middle one. If I’m not too busy fighting with traffic or the nanny systems, I’ll wave back.


The original Peterbilt 387 was a coal truck, made from 1975 to 1987. The name was re-used for this model, launched in 1999 and made through 2009 at the Denton and Nashville plants. It was designed to be more aerodynamic than its predecessors, and had two sleeper lengths, with a raised roof or mid roof, and a day cab option; a glider kit was optional. It was eventually superceded by the Peterbuilt 587, which was EPA SmartWay certified. Grille shutters aided aerodynamics as well. A variety of wheels were available — stud-piloted disc wheels (both regular and heavy-duty), PHP-20/Budd UniMount-10/WHD-8 series, and cast spoke wheels. Transmissions were made by Spicer, Fuller, and Meritor.  Drivers had a variety of computer-driven alarms, to show system faults, low air or oil pressure, and high engine oil, transmission oil, or coolant temperature. A small, non-random sample of owners reported 7-9 mpg. (If you can add more, please use the comments box to do so!)