Is it difficult to change a transmission mount on a C280? What's the procedure? Thanks.

Does a shudder that occurs under middle-load acceleration through 1600-2200 rpm indicative of a transmission mount? It only occurs at that range of rpm and usually in the gear where 35-40 mph matches those rpms. Thanks. Possibly other problems, i.e., drive shaft or center support bearing? Front "flex disk" was changed and the shudder seemed to appear not long after. At the time, mechanic said rear flex disk was fine and there was only a slight sagging of the support bearing not neccesitating a change.