I read the article in the archives on hunting down vibrations but, I was hoping to get some more opinions. My brothers 68 mustang coupe (351W/AOD) has a vibration that only happens at around 2500rpm. All driveline parts are virtually new(engine, tranny, alum driveshaft, rebuilt rearend) with less than 3k on them. On top this the vibration has only shown up over the last few hundred miles and he says that it just started doing it one day (ie he didnt run over someting or make any adjustments). Visually the drivetain looks intact and all mounts are properly torqued. Any ideas?