Our LG dryer's tumbler stopped spinning about a year ago without any explanation. At first we thought the motor was burned out (after only owning the dryer for just over 2 years, not very impressed with LG so far), but we noticed that we could still hear the motor hum... Just for kicks we decided to press the door closed button and manually spin the tumberl and all the sudden the tumbler started spinning on it's own again. We quickly slam the door closed and it runs just like it is supposed to... We've been doing this for a year, but I eventually want to fix it permanently. I haven't taken it apart yet, but I think it's one of these issues:

1. Worn drum belt
2. Faulty motor
3. Worn/faulty idler/tension pulley
4. Clogged/worn/faulty rollers that don't roll as well as they used to
5. Possible combination of some or all of these factors

Am I missing any other culprits? Are any or all of these hard to replace? The nice thing is we are not in dire straits and sitting here with wet/damp clothes, so we can order the parts online and hopefully get this straightened out... Thanks for any advice.