I spend $236 diagnostic cost at Mercedes of Denver on Colorado Blvd. .They couldn't find cause of rumbling in 2012 GLK 350 SUV at highway speeds but gave me estimate of $2000 in misc work that did not address the issue. They also claimed they checked that my lights and all ok. Well ...MBclinic...front lights out high and low beams needed replaced. Washer bottle broken but marked ok fluid level...wow... found metal in transmission pan..front differential, torque converter,replacement and front axles. Thankful for warranty coverage..$14,400 in repairs. All covered since I have a Fantastic repair shop. All my cars will only be serviced by MBclinic. Now my family is truly safe. Much thanks