Perhaps she's not a goner after all..

It's really a simple problem, if the drive shaft is spinning when it's in gear and the car doesn't move it's the rear end. If the drive shaft isn't spinning when it's in gear it's the transmission. Now go test it and let us know.
True but without any resistance the shaft could turn some if it was low of fluid.the OP should be able to tell if it is free spinning(revving very quickly) or is laboring to accelerate(rear end locked up) when he has it in gear and hitting the pedal.