John Joseph Degnan

my old vecu went bad in my mack 98 r model and truck would not start. I changed it with another one I bought used on ebay and truck started right up but will not go over 30 mph. called dealer and said I need to buy a new one because you cant put a used vecu from another truck because it wont work. they also said they cannot reflash a used vecu. just want some onpinions on this because I talked to ther people who put used vecu's in their macks with no problems.