Class-action law firm Hagens Berman, who also worked on the eventual $10 billion Volkswagen Dieselgate settlement, alleges that the Duramax diesel engines in 2011-2016 Silverados and Sierras are rigged with at least three distinct devices designed to only limit emissions under a narrow range of circumstances matching those found in emissions testing. On the open road, the lawsuit claims the 705,000 affected trucks pollute at rates up to five times higher than the legal limit.