We used a Silverado 2500HD Crew Cab 4WD hitched to a 9,000 pound ballasted trailer with a windscreen for the first run.
Equipped with the 6.0-liter gasser, we pulled onto I8 for an uphill climb against a 2007 Dodge Ram Quad Cab 2500 powered by a HEMI 5.7-liter V8, rated at 345 horsepower and 375 lb-feet, and a 2007 Ford F-250 Super Duty Super Cab with a Triton V10, rated at 362-horsepower and 457 lb-feet.
Both the Ram and Super Duty were pulling identical 9K trailers with windscreens.
We lined up against the Dodge and the Ford separately on the highway. When the trucks were even with each other at around 45 mph, the drivers signaled to each other to hit the gas and pound up the grade.
The Dodge, was quickly dropped but against the stronger V10 things got interesting. The Super Duty initially pulled away from the Silverado HD from 45 to about 52 mph, but from 52 to 70 mph the GM pulled up to and passed the Ford, and from 70 to 75 both trucks stayed the same distance apart from each other until both drivers took lifted the accelerator pedals off the floor. We’re chalking this up to the Chevy’s 6-speed transmission versus the Ford’s 5-speed. Both trucks were sporting 3.73 rear axles.
The second run up and down the hill was with the diesels. The Duramax cab configuration was the same as the gas pickup, but this time towing weight was bumped up to 12,000 lbs without a windscreen.
Unfortunately, GM wasn’t able to obtain a 2008 Ford Super Duty with the new 6.4-liter 350 horsepower, 650 lb-feet Power Stroke. These trucks just went on sale last week. A 2007 6.0-liter PSD hitting 325 horsepower and 570 lb-feet was the only Ford diesel available. Yes, the Chevy beat the Ford up the hill.
The Dodge also suffered similarly to the Ford. The Ram we drove ran with the smaller 5.9-liter Cummins I6, which has been replaced for 2007 with the larger 6.7-liter turbo-diesel that hammers out 350 horsepower and 650 lb-feet of torque. Yes, the Chevy beat the Dodge up the hill.
We’ll have to revisit this with another diesel shootout at some point in the near future.
So, forgetting the other diesel products on hand, let’s get back to the Duramax/Allison combo. For trailering, the Silverado has increased smarts in tow-haul mode to help engine brake the truck during descents at load. This was a spooky system before and it’s even spookier now at anticipating the point at where you’d want to downshift and then doing it for you.
Add in Allison's "tap shift" on the gear stalk, to manually shift the automatic transmission, plus the integrated trailer brake controller that works with the truck’s ABS system and trailers equipped with electronic-controlled brakes, and you’re talking fine tuning options for hauling trailers that allow the driver to so precisely control the rate of descent that the smell of burnt brakes and risk of manual misshift has almost become a thing of the past.
The Silverado Heavy Duty with tow haul, tap shift, and integrated trailer brake control is absolutely a professional’s tool.
By the time you read this story, regular and extended cab GMT 900 heavy dutys have already been shipping to dealerships.
Single rear wheel crew cab production starts on February 19th in Flint, Michigan and Dually production starts April 19.
And as the 2007 GMC Sierra and Chevrolet Sierra Heavy Dutys ramp up production levels, to make up 30% of all GM full size pickup sales, the engineering team is heading back to work next week.
2010 is just around the corner and that means another round of major changes to the Duramax to meet EPA requirements. Ford is hard at work on this challenge and Dodge says they can already meet it.
We can hear the treadmill clicking up another notch.