GM extends Cadillac CT6, Chevy Impala output to early 2020 GM extends Cadillac CT6, Chevy Impala output to early 2020 February 22, 2019 dzadmin Comments 0 Comment GM will continue producing the Cadillac CT6 and Chevrolet Impala large sedans until January 2020 at its Detroit-Hamtramck Assembly plant in Michigan.