SAN ANTONIO, Texas—Less than a year ago, gas cost more than $4 a gallon, and even the newest full-size pickup trucks weren’t selling as well as they were just two years ago. Owners were feeling the pain at the pump, too. Some sold their V8-powered trucks outright, or traded them for something more fuel-efficient. But core pickup drivers kept their trucks, because they needed the capability that only a full-size pickup can provide. In fact, GM says the pickup-truck market, now down to 1.6 million units a year, has shifted away from personal use toward buyers who really need the capability. So, can these folks have the both usefulness of a big truck with less sting at the pump? Perhaps.

Diesels are certainly a viable option at the highest end of the pickup-capability scale, but for light-duty trucks, the Chevy Silverado and GMC Sierra Hybrids offer the most frugal solution. We’ve extensively tested the Tahoe and Yukon Hybrids. And GM has installed that same system in its pickups and promises 40 percent better mpg around town and 25 percent better on the highway. These trucks can tow up to 6100 pounds (5900 for 4WD), carry a 1400-pound payload, and deliver better than 20 mpg combined.

We traveled deep into the heart of Texas—land of the pickup—to find out if these new hybrid trucks have the capability and efficiency we crave. Let’s find out. —John Stewart

The Specs

All Silverado and Sierra Hybrids are short-box crew cabs, with a bed length of just over 69 inches. And all are powered by an aluminum-block 6.0-liter V8 with GM’s two-mode hybrid system. The hybrid system consists of a 300-volt battery pack, stored under the rear seat, a two-mode, continuously variable transmission with four fixed gears, and a system of computer controls that blends power from the electric motors and (or) the gasoline engine according to driver demand. The operating system software constantly checks battery condition, load and road conditions to supply the optimum solution for varied demands.

The system is nearly identical to the one in GM’s SUVs and generates a total of 332 hp and 367 lb-ft of torque. The V8 can also operate as a V4 under light load conditions to save fuel, and regenerative brakes are used to recharge the battery pack. The Sierra and Silverado Hybrids can run on battery power alone at speeds of up to 30 mph. Electric motor assist also allows the engine to operate in V4 mode longer, and supply torque so that a taller rear axle ratio (3.08) can be practical without a loss of capability.

Unfortunately, the aluminum hood and some other weight-reduction strategies used in the GM Hybrid SUVs were eliminated on the pickups. Why? Because these expensive parts were considered too pricey for the pickup market. However, some efficiency measures were retained, including an electrically powered air-conditioning compressor and low-rolling-resistance P265/65R18 tires. A separate 42-volt electrical power supply runs the power steering pump, translating into gains of about 0.5 mpg. A soft tonneau cover improves highway mileage by a like amount, GM claims.

EPA estimated fuel economy for 2WD models at 22 mpg city and 21 highway; 4x4s are rated at 20 mpg city and 20 highway. That means a 4×4 Silverado or Sierra Hybrid, with a 26-gallon tank, has a range of over 470 miles. The Hybrid’s highway rating is based on savings from cylinder deactivation technology, a tall 3.08 rear-axle ratio and the potential for the electric motors to assist on uphill driving when the engine is operating between 1800 and 2400 rpm, allowing the engine to run in V4 mode longer.

The Drive

Our morning drive took us around San Antonio on mostly two-lane highways with lots of stop-and-go traffic and speeds generally under 55 mph. The drive was designed to demonstrate the Hybrid’s strength—city mileage. At low speeds the Hybrid emits a low whir, as it moves under electric power. We kept a light foot on the throttle and were able to maintain electric-only propulsion at speeds just above 20 mph. Even with an 800-pound load of sand bags, we could stay in electric mode up to nearly the same speed. The transition from engine to electric motor is fairly muted. There is little change in sound or vibration when the V8 activates, and many times we had to look at the instruments to know when that big engine decided to kick in. The transmission shift is seamless and there is no hunting between gears or propulsion sources—and no hard-shift impacts under throttle either. Instead, the transmission always seemed to have the right gear for the situation. So, with the air conditioning off the entire time, we averaged 21.0 mpg in a four-wheel-drive GMC Sierra Hybrid. At high noon, when air conditioning was needed (hey, this is the southwest, after all), our fuel economy dropped slightly to 19.6 mpg.

These Hybrids don’t drive the way one might expect a high-mileage pickup would. There is a torquey feel off the line, and a steady, linear response to throttle. Driven flat out from a standing start, the Hybrid is reminiscent of a regular gas V8-powered pickup. And it can hit 0-to-60 mph, GM says, in less than 8.4 seconds.

The brakes feel strong and remarkably progressive for a hybrid. Many hybrids have two-stage braking, in which light braking recaptures energy and sends it to the battery. Hard braking initiates the hydraulic system. In most cases, there is a difference in pedal feel between the two stages, which can be disconcerting. In this case, the transition between the two braking modes is minimized, and the brake pedal felt relatively consistent from top to bottom. ABS, traction control and stability control are all standard equipment.

A new feature on GM’s full-size trucks this year is a single hydraulic body mount, located midcab on the passenger side. According to GM product engineer John Turzewski, this mount improves rough-road ride quality and reduces hop on concrete highway slabs. The new mount seemed to make a difference on rolling pavement, smoothing the typical jar of the leaf-spring suspension at mid-to-high speeds.

Back at base camp later that afternoon, we switched to a two-wheel-drive Hybrid, loaded with 800 pounds of sand bags and hitched up to a 5200-pound boat. Our tow loop was brief, but there seemed to be plenty of power to do the job, and the two-stage rear leaf springs kept the attitude of the truck flat and level. We were told that the 6100-pound max tow rating was related more to the capacity of the cooling system than that of the engine, brakes or transmission. We did quite a few stop-and-go city traffic loops with the boat in place, and checking the mileage computer, saw we were logging 13.9 mpg.

The Bottom Line

The 4WD Silverado Hybrid we tested cost $45,985 and was loaded with leather, sunroof, power-adjustable pedals, a navigation system and just about every other option on the list. But with a base price of $38,995, it wouldn’t be hard to get a nicely equipped Hybrid for around $40,000. The Silverado and Sierra Hybrids are full-size pickup trucks that look, feel and drive just like any other Silverado. The difference is the Hybrid gets 20 mpg city and 21 mpg on the highway. To get that economy, you do give up some rear-seat storage area (because of the battery) and some towing capacity.

You can get similar highway mileage from Chevy’s less expensive XFE pickup, and a little better towing capability too. But the XFE can’t come close to the Hybrid’s city mileage. Additionally, you settle for a smaller V8, less torque and less horsepower. And you don’t have electric motors to overcome the tall 3.08 rear-axle ratio. Plus, there is no such thing as a four-wheel-drive XFE. The Hybrid may cost more, but it does offer a unique combination of power and economy. GM truck line executives are already promising better packaging and performance from the next generation of hybrid trucks, due in about 4 years. We can’t wait.