Thom Cannel: Article & Photos
Zane Merva: Photos & Video
June 25th, 2019
By now you prospective 2020 Chevrolet Heavy Duty owners are over the Ho-Hum of our 2020 Silverado 3.0-liter story (we are totally Ho-Ho-Ho and Hmmm, can’t wait for a longer test!) and looking at the Alpha Dog, the 35,500-pound tow-rated Silverado Heavy Duty and its over 50 industry firsts including an updated diesel engine and all-new 6.6-liter gas engine. Let’s get to it.
Where to start? With its amazing trailer towing features that include 15-view camera and ability to memorize the features of five different trailers? How about the Durabed with its class-leading cargo volume and all-steel construction with a plethora of cargo tie-downs? Maybe you’re gobsmacked by the corner and bed steps with, now, plenty of toe room and 500-pound weigh-holding capacity? Is it the power tailgate that remotely lifts or lowers? An ability to hold first gear while towing maximum weight? Or, is it all of these?
Chevrolet states that Heavy Duty trucks are working vehicles, whether towing a gooseneck horse trailer or flatbed and whether gas or diesel-powered. They further tell us that, compared to light duty trucks where 84-percent are retail and 12-percent go to fleets, Heavy Duty buyers are 70-percent retail and 30-percent fleet. Further, Work Truck and Custom trucks make up the volume; LTZ and High Country capture an even larger share of the market for personal and dual use buyers, with mid-trim LT trucks straddling fleet and personal use. Hence the five available trim levels to suit the needs of every buyer.
There is no mistaking that the 2500HD and 3500HD is kin to the 1500, yet only roof sheet metal is common. Everything about the new HD trucks was designed to be functional from larger grille to lower side-height bed, to improved box and bed steps. It’s massively bold with strong character lines, huge fender wells and functional hood scoop. Both the 2500HD and 3500HD are distinctive and clearly Chevrolet.
For 2020, every frame is boxed and steel, there’s a model with built-in gooseneck cross-body reinforcements and bed holes, 4X4 models can option Autotrac two-speed electronic transfer case, the DEF tank is relocated inside the frame rails with the filler under the fuel door, plus a 10-segment DEF gauge measures content.
A statistic to toss off at your microbrewery; within the total HD segment, 54-percent are Crew Cab diesels while within fleets, 62-percent are gas-powered, with 34-percent of fleets buying Crew Cabs and diesel power. And if you’re wondering where the 2020 Silverado HD you’d like to scope out on your dealer’s lot is hiding, Crew Cabs began delivery last week with Regular Cab, Double Cab and Duallies hitting the streets this fall. Restrain yourselves.
Let’s now talk about the biggest reasons for owning a Heavy Duty Chevrolet (or GMC). It’s towing. And if you’ve noticed comments to our 15-camera article, there’s some passion about technology. Realistically, as many HD trucks are sold to new truck owners towing large RVs, anything that improves road safety is flat wonderful.
If you further read Chevy’s research that says 12-percent of pickup drivers have gotten into a fight with their significant other over trailer hookup, you’ll understand executive chief engineer Tim Herrick’s comment that “We save marriages.” Having driven every truck segment from light duty to tractor-trailers we feel you. So, when research says a majority of drivers are stressed by towing, please offer them a 2020 Silverado sales brochure and a tissue (and save a tissue for yourselves ‘cause you might be exaggerating your tow-cool).
So let’s dive deeper into the subject.
Everyone has a hitch camera these days, with overlaid guidelines to put you within a few inches, front-to-back, of the ball. Chevy goes further with a selectable view that looks own over the ball. Even those who haven’t set a hitch in years—or never—can get within a quarter-inch of perfect. And an APB or automatic parking brake engages automatically so that when you lift off the brake pedal you don’t roll off the ball.
Sticking with the non-pros and semi-pro haulers, there’s a checklist for your trailer, the ability to check the lights after connecting the trailer’s electrical system, a tow-haul reminder and VIN-specific labels for the trailer itself. If you option the smart trailer integration, which is designed to work with ASA Electronics iN∙Command® control system, you have control over trailer features like heat and air conditioning through the infotainment system or the myChevrolet mobile app. And nobody should turn down the ability to monitor trailer tire pressure and temperature. Blowouts are never convenient and most often low-pressure and highly temperature related, according to Michelin Tire Company.
We found the 15-view system difficult to get used to during the first five minutes, particularly when backing; our mirror habits are embedded. Yet, simulating tight turns where we could see along both the tight and far side, pulling forward into a tight box, or backing (after a few tries), we really came to appreciate what the system could do. Then, on the highway with an 18,000-pound box trailer behind us, mirrors just didn’t cut it compared to the high-tech camera system.
We were driving on twisting two-lane blacktop in mountain foothills. Using the entire camera tech set, particularly the ability to look out the back of the trailer, we could easily pick places to pull aside to let faster cars pass us. It took less than an hour to become a must-have feature. Later we towed a smaller skid-steer on a flatbed without the system and truly missed it despite using our slide-out mirrors fully extended.
This naturally leads to the two engines offered in the 2020 Heavy Duty, first the 6.6-liter V-8 purpose-built gas engine that delivers 22-percent more torque than its predecessor. Now it delivers 401 horsepower and 464 lb-ft of torque. It’s mated to a six-speed automatic transmission.
The 6.6L isn’t a just a 6-mm stroked 6.0L, rather it takes advantage of the Gen5 small block architecture and has a unique cast iron block with forged powdered-metal connecting rods and forged crankshaft. The most significant change is the addition of Direct Injection. It’s all new, an industry first for the heavy-duty market and new to GM trucks. Direct Injection allows a compression ratio of 10.8:1 Quoting Mike Kociba, a GM engineer and part of the Small Block team, “Our suite of changes allows us to hit class-leading gasoline engine torque, at 464 foot-pounds at a lower engine speed than the outgoing six-liter was optimized for. I'm proud of its 401 horsepower, which is SAE Certified; no games, it’s legitimate. Customers can have confidence they're going to tow whatever trailer they need.”
Don’t forget the larger cooling fan and newly designed water pump. The pump drives the fan through a one-inch shaft with unique bearing design to handle greatly increased thrust loads. Plus, the oil pump is now has variable output, so there’s less parasitic losses.
The 6.6L engine features an aluminum oil pan, nylon 6-6 air intake, and stainless steel exhaust manifolds unique for the Heavy Duty market. Like related light duty Gen 5 motors, this motor has variable dual-equal valve actuation, massive Gen5 valves and uses an actuator that’s mounted to the front cover to control intake and exhaust valves. The new block features inter-bore cooling, that is, coolant flows through Siamesed bores, notably in the upper bores where there’s a tendency to generate higher temperatures.
“Small engines with turbochargers allow them peak torque off idle,” Mike told us, “but for heavy duty we don't want that complexity. For the Heavy Duty segment we (General Motors) have durability requirements—Global Engine Durability—that are unique stringent. We know our customers and why we focus on durability. If they can't use their truck today, they might not get paid.”
When towing a heavy load, we loved the diesel’s engine braking capability. What about the gas engine? In Tow-Haul, up-speeds caused by downhill driving—together with intelligence based on throttle position—the powertrain produced seamless downshifts. It’s not quite the same as engine braking, but the trailer was “only” 12,000 pounds. Regardless, it was a comforting addition to stress-free towing.
The six-speed transmission used for 2020 Heavy Duty GM trucks is an updated 6L90 with an uprated torque converter and clutch pack. According to GM engineer Rich Mardeusz those changes were simple. When it came to the torque converter, things changed. “We looked at the components from a heavy-duty diesel torque converter and a high-output gas torque converter and then took the torque-carrying components from the diesel and married them to the spring and damping components from the gasoline torque converter. That’s what was needed to accommodate the approximate 22 percent across-the-board torque increase.” Those changes also damp out firing frequencies from the gasoline V-8 engine, making the powertrain smoother.
Since a majority of buyers opt for the diesel engine, let’s look at that. Also displacing 6.6-liters, the Duramax turbo-diesel makes 445 horsepower and 910 lb-ft of torque. It’s coupled to a 10-speed Allison transmission. There were minimal changes to the engine for 2020. They include a 28-inch fan for cooling; upgraded oil cooler—now 19 plates instead of 14 and the cylinder head gasket was improved.
Engine brake capacity is greater by 14-percent and while there’s a button for manual activation, while in Tow-Haul mode engine braking is automatically activated at certain RPMs. It’s Chevrolet keeping you safe.
Thus, under the new control system the powertrain will recognize any need for the engine brake and activate automatically. For instance in driving down hill and forgetting to shift, the higher RPM means automatic activation.
We did experience this with the18,000 pound box trailer and it is amazingly transparent and surprisingly quiet. You don’t have to downshift on modest hills, as the system will totally keep you at, or near your desired speed. Of course you may have to use a bit of smooth brake application if the grade is longer, or steeper. For really steep downhilling Plus-Minus buttons on the column-mounted shifter initiate gear changes. We’re not huge fans of the buttons as the steering wheel obscures their location and make it a bit fumbly to slide your thumb into position.
A really important feature for 2020, diesel models add an engine after-run feature. Should you tow up a grade and park for dinner without a cool-down, the truck will do it for you. Run time is limited by temperature and shutdown is equally automatic.
Because of the Allison/GM 10-speed transmission used for 2020, the powertrain required a complete recalibration. There are several positive results, according to David Ames, GM assistant chief engineer and Allison liaison. “Emissions have been improved and fine-tuned to maintain the best efficiency the transmission can offer to our customers.” It also has a fully warranted chain-driven engine-speed PTO available from the factory.
The new 10-speed’s torque converter has a lock-up clutch that is unique as it will lock up in first gear, even under max loads. So, if you're pulling 35,500 pounds, you can do a first gear launch and lock up right away, which helps get rid of heat. We asked David why this is important. “Normally in first gear you're under high torque and generating a lot of heat, which puts a lot of demand on the cooling system. Locking up gets rid of that heat. Also, the new transmission has a lower 4.5:1 first gear with four planetary gear sets and six clutches. We noticed the low gear and ten speeds on launches and while pulling the box trailer on the highway. Often in hilly driving you're downshifting to save brakes; with ten gears we held the right speed and best RPM, particularly with automatic engine braking.
We did drive a Silverado 3500HD dually at max capacity; 35,500 pounds on a closed course: our US Army CDL permit has lapsed. The claim of off-the-line torque is spot on. What was most interesting was the 3500’s ability to resist being pushed about on turns and we did several random serpentine loops to see if we could find any significant push? Nope. Later, with “only” 17,000 pounds behind us we finally found a bit of trailer push, which required a deeply rutted dirt road and an off camber turn. Nothing the truck couldn’t handle, even with a journalist behind the wheel.
Many of us wondered why the different transmissions for Heavy Duty trucks, why not just the Allison ten? We asked and, while suspecting that plant capacity utilization and raw costs have something to do with it, were told by Vincenzo Verino, the 3.0L Duramax global chief engineer “It’s really about what the transmission brings to the engine itself. With a wider torque band, the gas engine is well-matched to a six-speed, while the narrower torque band of the Duramax is better suited to a 10-speed.”
In the battle for Heavy Duty supremacy, big numbers are thrown around to convince potential buyers of worth and value. We found these slides from Chevrolet’s presentation compelling, showing Chevrolet doesn’t always have the biggest power numbers, yet can deliver more real world competency than competitors. Faster to 60 with better towing capability, we’ll take that over a bigger number any day. And Chevrolet says every diesel dually will tow more than 30,000 pounds the 2500HD with 6.6L gas engine has a tow capacity of 17,400 pounds, up 18-percent, that’s good regardless altitude.
There is much, much more to tell in future stories, like the no-cut removable fascia for winter snow plow installation and the covered fender-mounted engine heater outlet, use reports of the up-down power tailgate and the bed’s 12 fixed and 9 moveable tie-downs. There’s details on improved axles, locking rear differential, beefed-up prop shaft and 12-inch ring gear, stronger U-joints, class-exclusive SLA front suspension (“mandating a solid front axle for HD trucks isn’t a thing” according to the chief engineer Tim Herrick) and the list goes on.
We expect to write several more stories about the new trucks, each specific to how you’d use the truck and with even more details. We have only scratched the surface.
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