I can't seem to find out how to remove the trucks from an old f9 8 wheel drive to upgrade the couplers to magne magic. Bachmann did not reply so I'll ask here. You tube does not tell me

Is it a Bachmann product? If so, an exploded diagram ought to be in the parts section of the website.

There are several versions of this locomotive out there. You said it was 8 wheel drive. Is it one from the early 1970s, with the big pins that hold the trucks in place? Or is it one of the newer ones in the white or blue box?