Does anyone know where I can buy the aluminum thread-on belt pulley for this dryer’s motor without having to buy the whole motor? 
I have looked around and do not see it listed as a separate part. I recommend you contact Maytag and see what they say.
Good luck, and let us know if you can get it.
I just had the same problem, after replacing the belt and idler pulley I narrowed down my problem to a stripped reverse thread pulley on the motor.
Like everyone else I couldn’t find a replacement part and since the motor tested fine I didn’t want to pay $150 for a new motor when I needed a $2 pulley.
I simply JB Weld’ed the striped pulley onto the arm so far so good the drum is turning, now the only question is how long will this fix hold up.
Ray
rayhanson72
Here is a similar problem I answered a while back.
http://forum.appliancepartspros.com/dryer-repair/514771-dryer-motor-pully-loose-motor-shaft.html?highlight=pulley
Unfortunately the poster did not get back to us on how it went.