Pin swap

I now have a problem like the wiiggly motor problem thread by Baustard. My problem is with the extruder drive (E0). I've moved the carrier and extruder motor from E0 to Z and it works fine. I've moved the Z motor and carrier from Z to E0 and the motor indexes in seemingly random directions but never more than a few degrees. The only thing I haven't tried is moving the carrier and motor to E1 and that's what I'm asking for help with. I did try to tell marlin that I have 2 extruders but I got an error when I tried to upload the sketch. I'll do it again and make note of the error if that's an important part of the process for the thing I'm trying to achieve.
Thanks!
joe

The error is almost always important.

But an easier way to do this is to alter pins.h, swap the E0 and E1 pin definitions.

That's what I was hoping but I didn't know if there was anything else to consider. Off hand, do you know if these pins are hardware or software?

They use Arduino digital pin numbering.