General Motors retirees facing the loss of their health coverage should shop around aggressively to save money on Medicare coverage, say Ford retirees who went through the same thing in 2007. They say it's actually possible to save money, despite losing a generous, company-backed health plan and having to pay to supplement Medicare coverage. A big part of the reason is a payment the auto companies are giving retirees in place of their coverage. John Pottow, an associate professor specializing in bankruptcy law at the University of Michigan Law School, said many other retirees could face the same choices in the coming years.