Vehicle Shudder problems of the 2010 Chevrolet Equinox

Car vibrates vigorously at speeds between 10-25 mph. Hard to control in city driving.

The contact owns a 2010 Chevrolet Equinox. The contact stated that while driving at 25 mph, the vehicle vibrated severely and an unknown sound was heard from the rear of the vehicle. The failure recurred whenever the vehicle was operated. The vehicle was taken to a dealer where it was diagnosed that the transmission had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The vehicle failure mileage was 125,000.

My wife was driving home from work to eat lunch as with any other day and all of a sudden the vehicle started shaking violently, the check engine light came on along with a "reduced engine power" message and an exclamation mark. I've done a ton of research and have seen this show up as a common issue with many gm models. I found the gm TSB 11273 that describes the exact condition we are having. Want to know the problem? my wife's 2010 Equinox isn't listed in the TSB!!! I do not understand this at all. I've called gm to explain the situation and they will hear nothing of it and are telling me they will not cover the expense. It makes no sense to me how they admit fault and pick of the cost of the exact same repair on other gm models but they will not pay for the repair on my vehicle for the exact same problem. This is a very dangerous issue and I couldn't even imagine having this issue at a high speed, luckily my wife was only driving in town. This is unacceptable. To make things worse, the vehicle doesn't even have 55,000 miles on it and gm is telling me the 5 year 100,000 mile powertrain warranty doesn't even cover this! how much sense does that make? the powertrain is the meat of the vehicle which cannot be utilized if the throttle body is acting up because the vehicle is kicked into reduced power mode! very frustrated with gm's customer service in not acknowledging this issue should be fixed.