My question is. will different year PCMs for the LMM duramax interchange? for example when I try to flash a ecu from a 2008 duramax to a 2009 sometimes it works but alot of time I get an error or a TCM OS mismatch,

im looking for a way to do the LMM ecu out of truck for projects.

I can get a good price on used ECU but rarely are they the right year,

can anyone help with interchange?

thanks