Another transition at TriMark USA, the Mansfield, Mass.-based multi-brand national dealer (and the country’s largest). Tom Schrack Jr., who has served as president at Omaha, Neb.-based Hockenbergs and TriMark Hockenbergs for the past 17 years, will retire effective Mar. 1. Schrack was president when his family sold Hockenbergs to TriMark in 2017. He has long…