I have a clunk sound emmiting from the rear of my 190D whendownshifting to first gear that needs to be taken care of (when it gets non-cold outside).So far I've concluded that it's probably a bad flex disk or rear subframe bushing, worst case scenario a bad vaccum pump. But does anyone know where the rear subframe bushing would be and what it would look like? I have not inspected the flex disk yet, but I knowwhere thatis and what it looks like. Thanks!