I have a 2004 ford f350 6.0. It ran good until this pandamic and I parked it. I decided to drive it the other day but the batteries were down. Charged them and truck started easy. Put it in gear and truck died. Started it back up and same thing. Put the AE on it and it showed all kinds of oped circuits and sensors out. I thought a squirrel had got to the wiring but could find where any had been chewed.
I changed the ecm and it started up and would go in gear but now It will not move feels like it is going into several gears at once and no reverse, also it will not rev up but a about 1000 rpm.

Anyone ever had something like this?

Thanks