Maytag dryer makes rumbling ...buttt...

When starting or stopping maytag dryer makes a rumbling sounds like the belt is not allowing it to start right up like it is slipping but i took the small cover off the back and it seems like the belt still has tension from the tensioner …when it stopps you can open the door real quick and it makes the noise and the drum will stop then seems like momentum will make it move slighty before it stops again …i saw the fan blower posts i duno if this would do that or not or my drum motor is shot …still heats well just seems like it needs to spin a lil bit to get going and stopping like then it catches and goes…?