General Motors is giving the an entirely new V6 gasoline engine with cylinder deactivation and an eight-speed transmission for 2017. Apparently the idea is to give the truck better performance and economy, which sounds great. But GM’s estimated new 0-60 mph and MPG figures? “Essentially [a] carryover” from the old truck. Boo!

The truck’s Chief Engineer Stan Ludlow broke it down like this:

“...for the new V-6 and eight-speed combination we focused on improving everyday driving performance. Drivers will immediately notice that it pulls harder when accelerating from a stop or passing on the highway; it is more confident pulling a trailer up a steep grade and it is more refined cruising at a constant highway speed.”

Intriguing, but ambiguous. I don’t know about you, but I “notice” my car “pulls harder” after a fresh wash.

The 2015 and 2016 Chevy Colorado’s V6 was a 3.6-liter, and so is the 2017's. But we’re told that’s pretty much where the similarities end. GM’s truck communications chief Monte Doran told me the new engine and the old one have “identical displacement and configuration, but share virtually no parts” in an e-mail.

More specifically, the new features for the powerplant include “improved variable valve timing for intake and exhaust, improved direct injection” and cylinder deactivation which shuts down two cylinders “under light throttle applications.”

The new V6 is rated at 308 horsepower at 6,800 RPM and 275 lb-ft at 4,000 RPM. It’s a negligible increase over the previous engine’s 305 horsepower and 269 lb-ft ratings at the same engine speed.

The new eight-speed gearbox is a Hydra-Matic 8L45, which GM says is “roughly the same size and weight as the 6L80 six-speed automatic it replaces” so the new truck’s curb weight and payload capacities should be the same as the current truck.

The eight-speed has a numerically higher first gear ratio making the truck hustle harder off the line. A numerically lower rear axle ratio is supposed to improve fuel economy at cruising speeds. While the six-speed had a total ratio of 6.0, the eight-speed goes up to 7.0. That basically means the new transmission has a little more flexibility in picking the best gear for a given situation, helping the truck make the most of its engine output.

That transmission will be the V6 engine’s standard pairing for both 2WD and 4WD trucks, the six-speed will be completely done away with.

GM used the phrase “pulls harder when accelerating,” but when I asked Doran to quantify that with a new 0-60 estimate he said “it’s not going to be significantly different in terms of actual time, but will feel quicker behind the wheel.”

The sensation he’s referring to would probably be explained by the higher first gear ratio. That could give the truck a greater feeling of “surge” when you step on the gas from a stop without really adding accelerative power over a significant distance.

So 3 horsepower and 6 lb-ft of torque didn’t shave any time off the stopped-to-speed limit run, but I’ve got to believe the extra gears, lower rear ratio and cylinder deactivation will help fuel economy.

But apparently not really. “We don’t have EPA numbers [for fuel economy] yet, but expect it to be essentially carryover,” Doran said.

Now in fairness, it is possible that drivers will see “real-world” fuel economy gains even though the EPA doesn’t detect them in their testing cycle. I want to believe the Colorado will get better mileage with two extra gears. After all, when they were upgraded two years ago.

In case you’ve forgotten, the current V6 Colorado is EPA rated to 21 MPG in combined driving (and 18 city, 26 highway) with 2WD while the 4WD version gets 20 combined, 17 city, 24 highway.

I’m still a little confused on that part.

To recap: the 2017 Colorado V6 has an entirely new engine, with cylinder deactivation, and two more gears without adding weight to the transmission, for an expected gain of nothing on 0-60, nothing on economy, and nothing on hauling capacities.

Why develop a whole new driveline just to say the truck “pulls harder when it’s accelerating?”

There’s got to be some kind of supplier, emissions, regulatory or reliability reasons why the truck’s heart is being changed. We don’t know how much the ’17 Colorado V6 will cost yet, but has to be more than today’s truck to pay for that R&D.

I guess we’ll find out before the end of this year, when the new truck is supposed to hit dealerships.