I suspected the loud noise of the dryer was because of one or more bad rollers. The drum literally sits on the four rollers and nothing else. The front and back dryer panels keeps the drum in place. A belt around the drum driven by a motor makes it spin. The hardest part about the job is knowing how to access the drum rollers without having to take everything apart.
There are YouTube videos that help with that except I couldn't find one that showed my model. Most videos are for models that have a front control panel just above the door, whereas mine is located on the rear of the top dryer plate. I was able to find and download a service manual which shows that the top dryer place can be opened like a door as there are hinges on the back. You just insert a putty knife below the top plate in the front. There are two clips on either side that hold the top plate down in front. Insert the putty knife a couple of inches from the left/right edge and then push back each clip. Lift up the putty knife to raise up the top plate in front. You might need to tap the back of the putty knife with your palm. I also used a second stiff putty knife, using it as a lever to help raise the top plate once the first putty knife pushed back the clip and created enough space to insert the second putty knife. There's no need to disassemble the control panel or anything else attached to the top plate, You just raise it up like a door and then use something to hold it up while you continue to work on the dryer. With the top plate opened up, the rest of the job is the same as for front panel dryers shown on the YouTube videos.
I replaced all four rollers since I didn't know in advance which rollers were bad. Also, I didn't know how well the replacement rollers would match the original rollers. To avoid a potential drum wobble, I decided to replace all four of them and thus being assured they were all identical.
The roller assembly from AppliancePartsPros.com worked fine. It is possible to find just the rollers online. Although this is cheaper, you then have to worry if the parts from the old roller assembly will work with the new roller. The roller assembly does not appear to be OEM, however, aside from the color, I couldn't tell any difference. The LG originals are blue, whereas the replacement rollers are white. I'll have to wait and see if they'll perform like the originals.
The job itself can be done in less than an hour. However, I took the opportunity to vacuum out the loose lint that had accumulated inside the dryer over the years, as well as doing some additional inspecting/cleaning while I had the dryer open.