The dryer belt pully on the motor shaft rotates freely on the motor shaft and thus will not drive the belt. It cannot be tightend with a wrench almost as if the threads are stripped. Does the whole more need to be replaced or is there another fix?
Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=ADG7005AWW
Have you tried tightening it in both directions, may be a reverse thread?
The proper way to fix it is to replace the motor.
The jiggery pokery method is to drill through the pulley and the motor shaft and then insert a pin.
The problem here is that it has to go in very tight so it cannot come out.
Also once in you have to file/dremel the ends so that they match up with the ridges on the pulley. Or have it inset so it is below the ridges.
A lot easier just to replace the motor or if the unit is not in great shape replace the unit.
Seems like it is stripped. I’m going to try the drill and pin and see if it works. Not giving up yet. That motor shaft is probably fairly well hardened.
It should not be that bad to drill through.
If you have a good hardware store see if you can get a proper split pin for it.
They are made of spring steel so that once you pound them in they hold their position. Also one or both ends are slightly beveled to help driving it in.
Finding one that is the right size may not be possible.
You would need a dremel to cut them though as they are very hard.
I am not sure exactly what they are called but the below link should help with my rather poor description.
http://www.spirol.com/s/springpins_gaw/?gclid=CN6gmKuB17QCFelDMgode18AWg