Humming may be from the motor or incidental belt noise. There is a felt bearing on the drum where it rides on the front panel and this felt bearing can get dirty. I'm not convinced it would make a humming sound.
Tell me, what tune is it humming?
If you want to open your machine, generally speaking, dryer tops are held down with spring clips. To remove, pop the top by prying it up. Be careful you don't damage the finish. Front panels are generally held in place with spring clips and/or screws or tabs. Take appropriate action and remove the front. Be cautions of the door switch wires. The drum will come free and fall to the floor. Do what ever maintenance you feel needs to be done and reassemble. You may want to replace the belt while you are inside. I recommend you take pictures before you take the drum out of the cabinet paying particular attention to how the belt is driven through the tensioner on the floor and around the motor pulley. A cell phone with camera is particularly useful for this purpose.
Find replacement belts at a FixYa.com advertiser, local applliance parts place, LG website or www.repairclinic.com
I hope this helps you
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