If we were to have told you a few short years ago that The General would soon be producing mass copies of a rear-drive vehicle powered by a turbocharged straight six diesel, you'd have had us committed to the nearest madhouse. After all, such a bumf reads like sport European sedan from the eighties, when cars were cars and most passengers were terrified.

But it isn't a sports sedan, nor even a performance coupe. Getting inline at GM these days means moving into a Silverado half-ton pickup truck, the latest entrant from the Detroit Three in a quickly escalating war of diesel supremacy in trucks not competing in the Dreadnought-class. These are the volume trucks, folks, and all of the diesel powertrains - Ford, Chevy, and Ram - displace an identical 3.0L from their six cylinders.

Differences abound between the three, causing your friendly neighborhood gearhead's mind to temporarily out of control, even more so than it does after his third ration of Lamb's Rum. Let's dive in and decipher it all.

[Full disclosure: Chevy flew us to Oregon and put us up in a room for two nights. The program was focused on their HD pickups but a fleet of 3.0L half-tons were idling next door so, in a spurt of self-driven initiative, we took advantage of the opportunity assuming you lot would like a verdict on GM's newest diesel bundle of joy.]

The knock on any diesel is, literally, the knock. Those of us who remember the bad old days will clearly recall being able to hear a diesel-powered machine well before seeing it, emitting a distinctive clatter and plumes of acrid black smoke. The 3.0L straight six Duramax in this bright red Silverado RST exhibited precisely none of those traits. Thumbing the start button lit the diesel fires with a zing; if one wasn't paying attention, they'd might not even notice it was an oil burner.

At idle, parked between two other pickups to try and evoke maximum din to this driver's ear, the running Silverado 1500 Duramax produced only a whir, not a clatter or rumble. It was noticeably quieter than the Gen 2 EcoDiesel V6 from Ram, offered in the old Ram 1500 and current Ram 1500 Classic. We have not yet driven the Gen 3 engine, available in the new-style Ram 1500, but will be doing so later this summer. Stay tuned for comparisons.

Turning right out of the active airfield (duck if you see a plane!) we set off on a 25 mile loop which included a mix of rural and highway roads. Others, with their Christian motoring styles, routinely averaged an indicated 30+mpg on this route. Your author recorded 20mpg, driving the Silverado like a real truck with extended periods of idling for photos and giving it bootfuls of acceleration when appropriate.

Somewhere in between those two extremes is a real world number, one which will likely fall in the very high 20s for most owners. Unladen and on a flat highway in a 2WD model, 30mpg would not be out of reach. Our tester was a rear-drive extended (not crew) cab trim, representing one of the lightest Silverado trucks on offer. If you buy a Crew Cab 4×4 with a standard length bed, expect lower numbers. Sadly, official EPA digits are not yet available.

Price? The diesel adds $2495 of cheddar over the 5.3L V8, same as opting for the mighty 6.2L gasoline V8. Stepping up to the diesel from the 2.7L turbo will cost $3890.

At full chat across Oregon wilderness, the Duramax power team was content to upshift its ten-speed automatic just shy of 4000rpm. GM says all of this engine's torque, all 460 lb-ft of it, comes online at 1500rpm and sticks around until 3000rpm. Its power peak shoves out 277 horses at 3750rpm, which was approximately the shift point when the truck was left to its own devices. Chevy is clearly making the most of this engine and its power delivery characteristics, as the truck never felt boggy or down on grunt. It also never allowed itself to get near the 5000+rpm redline and the start/stop system was as good as invisible. Note well: Ford's F-150 Power Stroke makes 440 lb-ft at 1750rpm while the (new) Ram 1500 EcoDiesel posts 480 lb-ft at 1600rpm.

Cruising at 50mph, the Duramax emitted only a low grumble, as if it were located far away and ensconced under a thick woolen blanket. A full throttle blast from 50mph-70mph to simulate a highway passing situation took about five seconds, estimated using the entirely unscientific "one Mississippi, two Mississippi" counting method. If all hands would like to donate to the TTAC Fund For Real Equipment, please feel free to do so.

It'll go without saying this Silverado 1500 Duramax was unburdened by any trailer, though Chevy says it can haul 9300 lbs when properly equipped. For comparison, Ford claims a 11,400-lb limit on its F-150 Power Stroke while Ram boasts of 12,560 lb towing capacity for its new Gen 3 EcoDiesel.

Eagle-eyed truck spotters will be able to identify a half-ton oil burner by the chrome Duramax badge on the hoods of rigs so equipped, placed in the same location as that of those on the Heavy Duty trucks. Everyone wants to be a bit like their big brother, I guess. A side exit tailpipe will also spill this truck's diesel secrets. Your author is not offended by Silverado 1500 styling, at least not in this RST trim with its color keyed grille and bumpers. Those vertical ventilation jowls south of the outrageously narrow headlights are functional, by the way, allegedly creating an air skirt along the side of the truck to help improve fuel economy.

Which is the whole point of a 1500-class diesel, right? In a world where the half-ton gas burners can haul just as much or more than their torquey brothers, stellar fuel economy will be the killer app for these rigs. It is worth it? How long will it take to pay for itself? We strongly recommend you call up your math nerd buddy and have that person help you run the numbers, keeping in mind the price (and availability) of diesel fuel.

Straight six engines hold a lot of allure for gearheads, thanks to their unique NVH and sound properties. Silverado shoppers would be wise to sample this new mill, as the half-ton diesel class is no longer a weirdo option. Quiet, torquey, and responsive, it's never been easier to straighten up and get in line.

this review first appeared on TTAC