First Drive Review: 2011 Chevrolet Silverado 3500HD, Part 2

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In the Driver's Seat

After driving Ford’s Super Dutys, we’ve also fallen for the telescopic steering wheel for optimal driving comfort, especially during long towing trips when you want to be as relaxed as possible. We’d also like to see optional electrically extendable trailer towing mirrors, like what Ford offers, because it’s inconvenient to get buckled in and then realize you need to get out of the truck to manually extend the mirrors or have to ask the front passenger to lengthen the right-hand mirror to see better around the trailer.

Turn the Silverado’s wheel, though, and you immediately start to appreciate all of the changes you can’t see. There's a new recirculating ball steering box with a welcome 16-1 turn ratio, down from 24-1 in the 2010 Silverado 3500.

It’s the best steering we’ve ever experienced in GM’s HD trucks and compared with other heavies, and it’s near perfect. The feel is firm but not too heavy, and there’s less play than we’ve felt in the 2011 Super Duty, which also features new steering gears and improved on-road feel.

As we pulled out of a parking lot and onto the freeway, we immediately noticed another change. Even though the Duramax is stronger than ever, it feels like a mellower engine because power is evenly available throughout the accelerator pedal’s full stroke. In a separate conversation about the new pedal feel, Gary Arvan, chief engineer for the Duramax diesel, said we noticed the new throttle strategy that GM is using.

“We are being purposely linear with the throttle map,” Arvan said. “With modern diesel, where you have electronic throttle control [instead of controlling the throttle directly via a mechanical linkage], you have the ability to put 100 percent of the torque in the first 30 percent of the pedal [stroke], if you want. That can lead to jumpy behavior that we don’t want our customers to complain about in a heavy-duty truck. It’s there to provide really predictable performance of the product. There are cases where you can lead to the need to put the pedal down further, but at least you have very predictable slow-speed performance, which is attractive when you’re towing a trailer. If you need [more power] just put the pedal down further, and the results will show.”

It took some adjustment to get used to the entire pedal stroke, but once we did, the Duramax’s wide power band was there for the asking. Demands for increased power were always met without noticeable turbo whine and little turbo lag.

While we often think of a trailer’s weight as the primary characteristic that impacts towing performance, nearly as important is the trailer’s aerodynamic profile. In our case, the camper we pulled had roughly 100 square feet of front sail that we dragged through the air, though it was canted back at a slight angle.

As we drove, we battled strong headwinds that challenged the Duramax, even though the trailer was still some 8,000 pounds under the Silverado’s maximum conventional towing rating. Often, it required laying the pedal all the way down to pass slower traffic. Our truck had the standard 3.73 rear axle, which seemed to be a good compromise between pulling performance and fuel economy.

Exhaust Brake and Cruise Control

After manually controlling the Silverado’s accelerator for several miles and getting a feel for the latest Duramax as we started to climb into the mountains of west Maryland along interstates 70 and 68, we tried another significant all-new feature in the Silverado: the Duramax’s integrated exhaust brake coupled with cruise control.

Chrysler was first to offer an exhaust brake for its Ram HD pickups in 2007, integrated with the 6.7-liter Cummins diesel. This year, Ford and GM also offer it for their 2011 diesel-powered trucks.

An exhaust brake saves on wheel brake and transmission wear by clamping down the engine’s turbo vanes (Ford and GM) or reducing the exhaust aperture with a sliding yoke (Ram), creating back pressure to engine brake the truck. It also reduces the potential for brake fade during long descents, increasing downhill safety while towing. Like the Ram, the Silverado’s exhaust brake is push-button controlled, so you can turn it on or off at any time. Ford’s exhaust brake operates automatically at all times, without a push-button control for the driver to enable or disable it.

Updated June-18-2010 6:45 am PT: Ford's exhaust brake operates automatically at all times, not just during tow/haul mode as originally reported.

We’ve been extremely impressed with the Ram HD’s exhaust brake for the 6.7 Cummins diesel. It surely reduced the amount of foot braking we’d have done without it. And it sounded cool, too, so we knew it was working. Contrast this with our experience in the Super Duty, where it was difficult to tell when the exhaust brake was operating to reduce transmission downshifting and using engine compression braking to slow the truck, especially while going downhill.

Photo by Jim Fets, courtesy of General Motors

The Silverado exhibited the best characteristics of both the Ford and Ram trucks, making it our favorite exhaust brake to date. It performs quieter than the Ram’s exhaust brake and smoother, too, blending better with the transmission so it wasn’t as sharp during operation. It’s louder than Ford’s exhaust brake, and we could easily tell when it was working, especially when we turned engine braking on and off. When the exhaust brake was turned off, engine RPMs rose on the 5 percent-plus descents we were dropping through. When it was on, RPMs held steady or fell. Descents that might have required 3,500 rpm last year to hold downhill speed steady were around 2,500 rpm with the exhaust brake engaged. Nice.

What makes the exhaust brake even better is when you combine it with cruise control. We set the truck’s speed to 60 mph and relaxed as the Duramax and Allison combo adeptly kept our velocity in check within about plus or minus 4 mph as we climbed and descended long rollers. We didn’t have to manually apply the brake pedal, even as we descended grades as steep as 7 percent while we watched the brake lights of smaller cars and trucks flash on and off as they scrubbed their speeds.

“Once it sees zero fuel [requested] and acceleration [because you’re driving downhill, the exhaust brake] will intervene to slow [the truck] down,” Mikulec said. “It will change the [turbo] vanes in cruise control, without cruise control and in and out of tow/haul mode. Even in parking-lot maneuvers, where you’re heavy on the [wheel] brakes, you will get the exhaust brake to engage.”

In contrast to when cruise control was off and we had to mash the accelerator all the way down a few times while climbing uphill – again, part of the new linear throttle pattern that GM has programmed into the truck – the Duramax effortlessly supplied the grunt needed without excessive sound and fury when cruise control was engaged. And as the drive went on, we left it in cruise most of the time.

The only thing that would make cruising in the Silverado HD better would be adaptive cruise control, so the truck would automatically slow as we approached slower traffic in our lane and resume the set speed when we were clear of other vehicles.

Photo by Jim Fets, courtesy of General Motors

Improved Wheel Brakes

When we did apply the wheel brakes, we noticed a tremendous improvement in stopping power and feel over the old Silverado – a big criticism we had of the 2007-10 GM HD pickups.

For 2011, the wheel brakes have increased from 12.8 inches to 14 inches in diameter and widened from 1.5 inches to 1.57 inches. They feature a larger swept area for better stopping power, and the operating pressures have been changed to provide a firmer feel during application with less pedal travel required. The bigger brakes are a necessary improvement to reach higher gross combined weight ratings across the lineup. They are another big win for GM’s HD pickups.

As we fought strong crosswinds and headwinds, we also came to appreciate the improved stability the revised torsion-beam independent front suspension offers along with the revised asymmetrical rear leaf springs and stiffer frame. The whole truck felt much more solid than the outgoing pickup.

Some will dispute the Silverado’s long and short-arm double wishbone front suspension instead of a solid front axle, like the Ram and Super Duty pickups, but for long trips on the highway, it’s impossible to beat this setup’s comfort. By the time we reached our hotel, we didn’t feel exhausted or beat up.

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