Why does my dishwasher make a singing / whistling sound
Sure sounds like a worn-out bushing / bearing pack. The squeal will get worse with time and become a screech. If it is a worn out drive belt the issue is just as complex. I have looked at LG's site for this product and it seems that this is definitely NOT a DIY job. LG offers tech support and possibly repair locations. Unless you are an expert at replacing bearing packs / belts and have a lot of specialized tools, I would send it out for repair, or you might have the option of an in-house repair.