2015 Gmc Sierra 2500 on 2040-cars

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Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.

UAW rejects GM contract proposal but makes a counter offer

The United Auto Workers union said a new comprehensive offer made by General Motors Co late Monday to end a two-week-old strike was not acceptable and said it had made a new counterproposal. UAW vice president Terry Dittes said in a letter to members "there are many important issues that remain unresolved." The union is awaiting GM's next proposal. He said GM's offer came up short on many issues.  Dittes said GM made a "comprehensive proposal" at 9:40 p.m. Monday. "This proposal that the company provided to us on day 15 of the strike did not satisfy your contract demands or needs. There were many areas that came up short like health care, wages, temporary employees, skilled trades and job security to name a few." Dittes is the union's vice president for GM relations and the UAW's lead negotiator in these contract talks. "We have responded today with a counterproposal and are awaiting GM's next proposal to the union," he wrote. "Regardless of what is publicized in print or social media, etc., there are still many important issues that remain unresolved." The strike, in its third week, has cost GM more than $1 billion, according to J.P. Morgan analyst Ryan Brickman. He said the cost per day in potential profit is $82 million. However, another analysis, by East Lansing-based consultant Anderson Economic Group, put the losses at $25 million a day. And the effects of the strike are expanding. GM said Tuesday the strike has created a parts shortage that forced the automaker to halt production at its pickup and transmission plants in Silao, Mexico, temporarily laying off 6,000 workers. Silao is where GM builds its highly profitable four-door crew cab Chevy Silverado and GMC Sierra pickups. The strike has also forced GM to idle some Canadian workers, and many suppliers have been forced to halt operations. About 48,000 UAW members went on strike on Sept. 16 seeking higher pay, greater job security, a bigger share of the leading U.S. automaker’s profit and protection of their healthcare. 

GM recalling Silverado and Sierra HD diesel pickups over fuel gauge follies

General Motors is recalling 9,733 of its heavy-duty twins over concerns with their 6.6-liter diesel engines and dual fuel tanks. The recall covers some Chevrolet Silverado HD and GMC Sierra HD pickups from model years 2012 and 2013, although the exact dates that the recalled trucks were built isn't specified. There's also no mention of how many models come from Chevrolet and how many are from GMC.
The problem rests with the transfer pump responsible for moving fuel from the rear tank to the front tank - it could fail, resulting in an inaccurate fuel gauge. It hardly requires explaining, but a faulty fuel gauge could leave drivers in a situation where they run out of diesel.
GM will begin notifying customers of affected vehicles, who will be asked to report to their dealers for a free replacement transfer pump.