A fleet does not pick a truck from a menu. It hands the factory a specification: engine and horsepower, transmission, rear axle ratio, wheelbase, sleeper size, wheels, tires, whether there is an auxiliary power unit for the sleeper or a wet kit for hydraulics. Two trucks of the same year, make and model can differ by twenty thousand dollars on spec alone. So it is striking how little of that difference has ever been measured in public.
The only numbers anyone has published
In March 2017 Heavy Duty Trucking asked the head of what was then the NADA used-truck guide and a Volvo remarketing executive to put dollars on common spec choices. Nothing more precise has appeared since. The figures are dated, and they are the only ones.
| Specification | Effect on resale in 2017 | Status today |
|---|---|---|
| Factory automated manual transmission against a 10-speed manual | Plus 1,500 to 2,000 dollars; a Volvo I-Shift added 8 to 10 percent on a four-year, 500,000-mile truck | Sign has flipped further in favour of automated, see below |
| Engine of 13 litres or smaller in a sleeper | Minus 3,000 dollars | Untested since |
| Wide-base single tires in place of duals | Minus 2,000 to 3,000 dollars, depending on model year | Untested since |
| 6x2 axle configuration, one drive axle instead of two | Minus 6,500 to 7,500 dollars | Untested since |
| Unusual paint colour | About minus 4 percent | Untested since |
| Horsepower | A premium for larger engines exists; no dollar figure given | Open |
| Auxiliary power unit, aluminium wheels, sleeper size, axle ratio | Not quantified | Open |
Signs that flip
The transmission row shows why a spec table cannot be carved in stone. A decade ago an automated transmission was a resale risk, because used-truck buyers wanted the manual they knew. By 2019 automated transmissions were 80 to 93 percent of new builds, depending on the maker, and their resale value, as Transport Topics put it, was "now built into it." By 2026 FleetOwner puts them at about 92 percent of new builds. The manual has become the odd one out, and the discount has changed sides. Except in one place: in the West Texas oilfield, manuals still command a premium, because the work rewards them. A spec effect has a sign, a size, a date and a region, and all four can change.
Where spec ranks
Against the forces that move a used truck by tens of percent, the market tide, the segment, age and mileage, the channel, spec is a second-order layer. Individually, most items are worth a few percent. Stacked the wrong way, a 6x2 sleeper with a 13 litre engine, wide-base singles and an odd colour, they can take 8 to 12 percent off a truck relative to the mainstream spec. Stacked the right way, dual aluminium wheels, full aerodynamic package, mid-400 horsepower, they define what dealers call the gold standard, the truck that sells fastest at the highest price.
Medium-duty trucks have their own version of the rule. A truck rated at 28,800 pounds gross weight resells for less than one rated at 26,000, because above 26,001 pounds the driver needs a commercial licence and the pool of buyers shrinks. That is not a spec premium. It is a market boundary that happens to be written on a spec sheet.
Spec is where a truck's price is negotiated. The market and the mileage are where it is decided.
Sources opened
- 1Heavy Duty Trucking, spec'ing for resale, March 2017 · The only published dollar figures for spec effects
- 2Transport Topics, automated transmissions shift into high gear, August 2019 · Automated share of new builds and resale value "built into it"
- 3FleetOwner, used class 8 truck market guide, 11 September 2026 · Automated transmissions at about 92 percent of new builds; manuals in the oilfield
- 4Ritchie Bros, Cummins vs Detroit vs PACCAR engine reliability, June 2026 · Engine brand reputations, qualitative
- 5Work Truck Online, 20 spec'ing mistakes that hurt resale, July 2016 · The 26,000-pound licence threshold and medium-duty resale