Driving vehicle down freeway about 75mph heard noise and truck shut speeds down to about 60mph on a major freeway. Per mechanic lifter has collapsed and it has been a common issue that Chevy knows about. He said that it could have been alot worse by seizing the engine and causing harm to drive or other people around causing a major accident. There is a major safety issue to life and or death caused by this issue that has NOT been a concern and causing people to pay over $5000.00 for repairs. Chevy has known about the faulty lifters for years and doesn’t seem to care about safety concerns.