depending on age the brushes in the drive motor would be a good starting point. Remove the rear panel and have a look at how the motors mounted, indesit change things just for the fun of it so there's a few different methods. one is a long 10 mm bolt going from the front to the rear passing through the front and rear motor mounts on the tub, if its these undo the retaining nuts and pull the rods clear disconnect the motor plug and the motors ready to lift out. Others will have standard 10 mm nuts and bolts if its these remove and lift out another varient it 10 mm screws going into plastic retainers behind the motor if it's these horrible things carefully remove the screws for they've a habbit of the retainers breaking ! And finally theres fitted bolts looks like a a bolt with no head! just crew off the nuts and they fall out. Once the motors out with the shaft facing your woktop you'll see two black inserts one on each side about 1.5 inches long held in by two star head screws, remove the screws and if the length of the carbon inserts in lower than about half an inch replace them they're about an inch and a quarter long when new depending on manufacturer, they are sided and most holders will be marked right and left . turn the motor shaft by hand and the brushes should rub freely and fairly quietly on the com, if they make a whirring noise you've not fitted them correctly. refit the motor and plug it in and that should be you !
jim, November 2007