Maytag Dryer: Drum Not Turning

As fate would have it, our 4 yr old maytag gas dryer stopped working 1 month after I replaced our 4 yr old maytag washer. Problem: Drum does not turn. I can hear the motor running, gas burner turns on (can feel heat within drum). Does this sound like just a ‘belt’ issue? How difficult would it be to replace?