I was driving home from work at around 60 mph. Very sunddly their was a rattling metal sounds and then vehicle struggled to maintain speed. Before pulling off the highway at the next exit. On the exit ramp the engine turned off and would not turn back on. The vehicle was also stuck in neutral and not able to shift out of neutral for towing. There was no worning lamps or messages even after the noise and reduced power. Vehicle was towed to local dealership on Tuesday evening, as this was not scheduled it took them to diagnosis the issue as engine failure and recommending to replace the engine. The vehicle is a 6.2L GMC Yukon Denali with 23k miles. All service has been done at the dealer with no outstanding work prior to the engine failure. Where it gets more disappointing is the lack of information for time to fix. The replacement engine was ordered by the dealer on February 14th. As of February 28th they did not have any information….So i called GMC on that 1800 number listed on GM Document DCS6866 referencing customer satisfaction program N232413430. The first agent disconnected without filing a case. The second agent had to restart the process and was told that there was nothing they would do for 14 days after the case was opened before it would be elevated. When talking to the agent they denied any information related to the GM Customer Satisfaction Program or any knowledge of what seems to be a wide spread defect on 6.2L engines. The service and support for a $90k vehicle from, in fairness they have provided access to rental vehicle from a local auto shop. The vehicle is far smaller and different from our vehicle we purchased. The vehicle is still sitting at the dealership service center and is not functional until the engine is repalced.