1998 Gmc Sierra 1500 Ext Cab 4x4 Mechanic Special Needs Rear End 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.

GMC Syclone spools up a storm on Jay Leno's Garage

A storm was brewing on American roads in the early 1990s. That's when Detroit's automakers were producing some of the hottest performance trucks ever devised – models like the Ford Lightning, GMC Typhoon, and its flyweight pickup sibling, the GMC Syclone. Jay Leno just happens to have one of the latter in his garage, and took it out to showcase in this latest video segment. The Syclone was an exercise in absurdity, and could not only trounce any other pickup on the road, it could outrun anything else GM made and just about anything else on the road – beating Ferraris and Porsches off the line. In a pickup, for crying out loud. The kicker is that its engine wasn't such a monster, either: under the hood sat a 4.3-liter turbocharged V6 pumping out what would seem by today's standards to be an adequate 280 horsepower and 350 pound-feet of torque. Even the smaller of the EcoBoost V6s available in today's Ford F-150 produces more than that. But in a lightweight, compact pickup, those figures were enough to propel the Syclone to 60 in 4.3 seconds and run the quarter-mile in 13.6 seconds. Long before the dune-jumping Ford F-150 SVT Raptor or even the Viper-powered Dodge Ram SRT-10, GM made fewer than 3,000 Syclones based on the compact Sonoma (sister to the Chevy S-10) and another 4,700 of the Typhoon, which was mechanically similar but more practical (albeit heavier) wagon bodywork from the Jimmy. But as Jay aptly points out, the Syclone was the one you wanted. Scope it out in the ten-minute video clip above.

GM warning 800,000 owners that their cars may need oil changes more frequently than they say

The days of changing your engine oil every 3,000 miles are long gone thanks to most cars having automatic oil monitoring systems, but about 800,000 General Motors vehicles apparently have incorrect monitoring software that is leading to premature engine component wear. According to Autoweek, certain 2010-2012 Buick LaCrosse, Regal, Chevrolet Equinox and GMC Terrain models equipped with 2.4-liter four-cylinder engines could be going too long in between oil changes resulting in a higher-than-normal number of warranty claims for the engine's balance chain. The balance chain links the balance shaft to the crankshaft, and a worn one can produce higher noise levels.
As a fix, GM dealers will be reprogramming the software for the monitors in an effort to reduce the interval between oil changes, which varies based on driving habits and conditions. Through February 2015, the software update will be done at no cost to vehicle owners, but since this is not a recall, after that point, it will be up to the discretion of dealers as to whether or not they will charge for the service. What isn't immediately clear is whether GM plans on giving assistance to out-of-warranty customers who are experiencing engine issues from the worn chain.