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GM recalls select Tahoes, Yukons, Escalades for rear driveshaft issue

GM is recalling a number of its full-size SUVs due to an issue with the rear driveshaft assembly that could ultimately result in driveshaft failure. The actual number of total vehicles involved in the recall is small at just 1,789, but it’s spread out across the entire 2021 model year full-size GM vehicle lineup. That means a small number of every model is being recalled, including the Chevrolet Tahoe, Suburban, GMC Yukon, Yukon XL and the Cadillac Escalade and Escalade ESV. GM traced the issue back to certain driveshaft assemblies with ball bearings that were not properly heat treated. If theyÂ’re not properly heat treated, GM says that the balls may deform over time, causing noise and vibration. Continue to drive in this condition, and GM says the affected joint in the driveshaft assembly could seize, causing loss of drive power. However, the problem wonÂ’t present itself all at once, as GM says there will be a gradual increase of noises and vibrations before total failure. For those few owners with affected vehicles, GM says that it will replace the left and right rear driveshaft assemblies with properly-built units. Per usual with recalls, this will be done at your local dealership at no cost to the owner. If you have one of the recalled SUVs, expect to be notified mid-March. Related video:

GMC Envoy could be returning as GM files for 'Envoy' trademark

The GMC Envoy could be on its way back, if a recent GM trademark filing is any indication of the future. To be exact, GM's trademark filing is for the name "Envoy," and is applicable to "motor vehicles, namely, sport utility vehicles, engines therefor and structural parts thereof." A victim of the recession and high gas prices, the original Envoy – related to the Blazer, and more recently the TrailBlazer and similar GM SUVs – was discontinued after the 2009 model year. In today's SUV-happy market of low gas prices, unearthing the somewhat familiar Envoy name makes a certain amount of sense. As soon as gas prices start trending in the other direction, we'll all be saying the opposite, though. What this SUV will take shape as is the big question now. With the Chevrolet Blazer well and truly on its way, there's every reason for a GMC version of Chevy's stylish new crossover sporting the Envoy name. Another, less likely, possibility is a Traverse-sized vehicle to slot between the shorter Acadia (10 inches shorter than the Chevy Traverse) and the body-on-frame Yukon. GM could come out of left field and make the Envoy a Buick too. It fits the bill with the "En" beginning, and Buick undoubtedly has crossovers in the works. We think that's even more unlikely, but it's important to remember that we're still in the speculation phase. Soon we'll drive Chevy's new Blazer, and perhaps have more news then. Check in next week for that. Related video:

GM patent reveals new two-stage turbocharger

Modern turbochargers may be some of the best ever made, but performance is something that engineers are always trying to improve. According to GM Inside News, General Motors (GM) is hoping to alleviate some of the negative aspects of a two-stage turbocharger setup with a newly-patented design. The patent, that was filed on May 19, 2016, reveals a clever bypass system that allows the engine, a four-cylinder unit, to optimize both the low-pressure and high-pressure inlets for its respective functions. According to the filing, a conventional two-stage turbocharger setup is engineered to allow both turbines to operate simultaneously at low and mid engine speeds. At high engine speeds, only the low-pressure turbine works. The setup can't isolate either the low or high pressure side, which can impair low-end performance. GM's new two-stage turbocharger setup looks to eliminate this by linking the high-pressure turbo to the exhaust manifold through the high-pressure inlet duct. The low-pressure turbo is attached to the high-pressure turbo by a low-pressure inlet duct, which is linked to a connecting channel. A single actuator that is housed in the exhaust manifold creates a bypass that can opens the high-pressure inlet or close the connecting channel. Depending on what the engine load and speed is, the ECU guides the actuator—a single rotating spindle with discs corresponding to flanges on the high and low pressure sides—to isolate one of the two turbos. Isolating the turbos allow the respective inlets to be engineered for the best possible fluid dynamic performance. The setup should increase performance and decrease lag. There's no word on what car this setup will make an appearance on, but it will most likely be used in premium vehicles before trickling down to the rest of GM's vehicles. Related Video: News Source: GM Inside News, AutoGuide via GM Authority Cadillac Chevrolet GM Technology Sedan turbo patent engine turbocharging