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GM faces possible class action lawsuit over 8-speed transmission

General Motors has been hit with a class-action lawsuit from owners who allege the eight-speed automatic transmission found in several rear-wheel-drive Chevrolet, Cadillac and GMC models between the 2015 and 2019 model years has a defect that causes the vehicles to hesitate and jerk when accelerating or slowing down. The lawsuit was posted to ClassAction.org and spotted by GM Authority. Problems with GM's Hydra-Matic 8L90 and 8L45 transmissions have been well-documented on Internet forums and via complaints filed with the National Highway Traffic Safety Administration, with many reporting damage to their vehicles. The lawsuit was first filed in December in U.S. District Court for the Southern District of Florida but appears to have been transferred recently to New York. Autoblog sought comment from Theodore Leopold, the lead attorney for the plaintiffs. "These transmissions have a common defect," the complaint reads. "Drivers attempting to accelerate or decelerate their cars feel a hesitation, followed by a significant shake, shudder, jerk, clunk, or 'hard shift' when the vehicle's automatic transmission changes gears." The problem also occurs when the vehicles accelerate in a single gear, without shifting, the plaintiffs allege. "Drivers have reported that the shift is sometimes so violent, they feel as though they have been hit by another vehicle." The problem is believed to center on the transmission, torque converter or both. The complaint says it causes undue friction, causing hydraulic systems and gears to function improperly and sometimes leaves metal shavings throughout the transmission, leading to costly repairs and replacement of parts or the entire transmission. It says GM has known about the problems since shortly after it introduced the transmissions, and has issued 13 technical service bulletins, none of which have resolved the problem. GM declined to comment on the lawsuit. The plaintiffs say GM should have warned consumers about the issues and covered repairs under each vehicle's three-year/36,000-mile bumper-to-bumper warranty. They're seeking statewide classes in at least six states: California, Florida, Illinois, New York, Oklahoma and Texas.

2016 Chevrolet Colorado Diesel First Drive [w/video]

The first thing you notice inside the diesel Chevy Colorado is that it's quiet. Almost too quiet. A lot has been done to quell noise and vibration with this new powertrain, and it shows – or rather, doesn't. There's some characteristic diesel clatter at idle, but even then it's distant and practically disappears as you start moving down the road. At full throttle, when the engine is at its noisiest, the sound isn't particularly diesel-like, just a pleasant intake breath. The accompanying smoothness is almost eerie. When we ask where all the noise went, Chevy's engineers, marketing guys, and PR reps all explain that this refinement is what Americans want. We're still not sure. This is a truck, after all, and the diesel pickup customer is different from the guy buying a diesel Cruze for his highway commute. Chevy contends that they're also not the same as the buyer of a Silverado HD. Although this 2.8-liter Duramax four-cylinder has been in service elsewhere around the globe, its first US application is in the Colorado and its GMC Canyon twin. The engine puts out 181 horsepower and 369 pound-feet of torque, and it does so unobtrusively as a result of a lot of modifications for our market. To keep normal diesel sensations out of the cabin, the intake and oil pan both get acoustic treatments. A new, thicker material is used for firewall sound deadening. Redesigned balance shafts have tighter tolerances to increase smoothness. The diesel powertrain is smoother than the Colorado's gasoline V6. One of the more interesting and certainly unexpected vibration-reduction changes is a special torque converter from German supplier LuK equipped with a centrifugal pendulum absorber. This pendulum spreads from the center of the torque converter as engine speed increases and is tuned to absorb the four-cylinder's second-order vibrations, not just those in a narrow frequency band. It does an admirable job, especially considering the engine's biggish, 0.7-liter cylinders, which lead to bigger vibrations. The result is a powertrain that's smoother than GM's (not particularly smooth) corporate V6, which is available in the standard Colorado. It's quieter than a Cruze diesel and even out-softens some gas direct-injection engines on the market. Paradoxically, it may be the most refined of all of the Colorados. No vibration comes through the steering wheel, pedals, floorboards, or even the rearview mirror. But you can tell it's a diesel when you hit the throttle.

First 2015 Chevy Corvette Z06 engine blows up at just 891 miles

You've waited and watched and waited some more for the arrival of your 650-horsepower, $78,000 Chevrolet Corvette Z06. Finally, that joyous day arrives and you eagerly, but gingerly, begin to break-in the 6.2-liter supercharged V8 monster under your hood. Then 900-odd miles after delivery, your excitement grinds, quite literally, to a halt. That's what the owner of one 2015 Z06 claimed happened to him when a simple break-in drive resulted in a lunched engine. The owner, known as Lawdogg149 on Corvette Forum, says he was out breaking-in his car ahead of a January track event when it happened. "While making a pull from 35 miles per hour, I accelerated and shifted short of redline, and boom - the car began knocking. I pulled over and popped the hood. I could hear a loud knock coming from the No. 6 cylinder area along with a serious, grinding, metal-on-metal sound coming from the supercharger area," Lawdogg wrote. A subsequent trip to the dealer confirmed his concerns, with the service facility telling Lawdogg that the No. 6 valvetrain had failed. The dealer couldn't research the issue further, though, as General Motors requested the engine be returned for a more thorough evaluation. The good news for the Z06's unlucky owner, at least, is that GM will be covering the engine replacement under warranty, an expense that Corvette Forum estimates is a nearly $24,000 procedure. At this point, the two leading theories behind the engine's detonation involve a manufacturing defect – which could be why GM is so keen to tear the blown powerplant down – or a mistake on the part of Lawdogg. As Motor Authority points out, such an error could be something as simple as the Z06's owner accidentally shifting to first rather than third during his 35-mph pull. If, however, there's a deeper manufacturing problem with the Z06's engine, this might not be the only case we end up hearing about.