After the filter -- which you said you've already done -- next place I'd look at is the drain hose, especially at the point it connects to the drain under the sink. Easy to disconnect and examine. Look at the hose for kinks and look into the discharge outlet for obstructions. Leave the hose-end out and get a bucket big enough to allow fill/drain from the DW. Allow single fill/drain to empty into the bucket. Suspect you'll learn lots in just a few minutes.

Does your LG Front Loading Washing Machine smell like mildew? How about your towels? Have you owned your washer for a year or more? Try shining a flashlight directly back to the drum wall. Look in between the tiny grates. You will be horrified at what you see! What I saw was a nasty layer of mold and mildew that I could not reach to clean. The LG technician said to run a few cycles with 1/4 Cup of Cascade and 1 Cup of Bleach. So far I've run two cycles AND I tried squirting bleach directly through the grid with a spray bottle. No luck. Sure, its a little cleaner, but how many cycles do I need to run? And what about the the parts that are inaccessible to my spray bottle? I'm very allergic to mold. Little did I know that I was clothing myself with it everyday. That explains a lot in terms of how I've been feeling. I DIDN'T HAVE THIS PROBLEM WITH MY TOP LOADING WASHING MACHINE!!

Please allow me to post my opinion and experience on this stinky issue. I am the owner of a HE3T washer, and I am really unhappy with it, mainly because of the smelly and moldy issue, that crept up on us unexpectedly. My wife and I have 4 kids, so doing laundry is a daily affair, and not to be underestimated or procrastinated either... I am on the verge of throwing that ugly beast out of the laundry room for good. It is unbearably revolting to pick up an (alleged) clean towel to dry one's face just out of the shower, and "smear" moldy smell all over you. The vomit factor is very high on this one.... :-( However, I want to highlight a point, and that this issue is NOT an issue with ALL the FL (front loader) washing machines in general. Maybe just US made ones... Overseas, ( Italy ) where I grew up, FL are 99.999999% of laundry machines available on the market and this issue is completely unknown. To put it simply, I am now 45 years of age, I have lived in Italy 28 of those years, and I have never, ever, seen or heard of moldy smell on clean laundry out of the washer. Never. If you knew my mother (she redefines the word "neat freak") you would understand. Just the hint of a remote possibility of having mold in the washer and/or laundry, would bring that washer in the front yard in flames... Seriously, I believe US manufacturers have gone wrong somewhere in the making of this machines. They either cut one too may corners ( quality of rubber, maybe ?) or are attempting to reduce the amount of water in the cycle at the point where the quality of the rinse cycle is not an issue with them, and us as consumers are not part of the equation. I just came back from a one year of living in Italy with wife and kids, and the FIRST thing we notice, ever single time we go over there, is how much fresher and overall incredibly better smell of "clean laundry" they have from their washers. I know, we are weird... and on the contrary, as soon as we are back to the US, and to our $#@! HE3T, we pick up the moldy smell again. The customer/user/consumer SHOULD NOT have to do any gimmicks or use any "special" tablets, in order to operate these washers, or any washer, for that matter, NOT A SINGLE ONE. This washers are NOT cheap and they should just... well, work. Living in Italy for the last 12 months, we used two washers, one that came with the apartment we rented, and besides a slower spin cycle, it worked as expected (put dirty clothes in, put detergent, push the button, wait, get wet CLEAN laundry out, END OF THE story. Then the landlord needed his washer back, and for a "rent discount" he took that one back, and I got my old 12 years old Miele washer out of storage. This Miele has a somewhat smaller load capacity than most, and it worked for a family of 6 for a long time. Same for my mother's Candy ( Italian brand), and my sister's old Italian washer (San Giorgio). That one lasted 16 years of day in and day out operation for a family of six. It is just so frustrating, since I know that as a concept, FL do work very well, I have seen it work for decades... and one more time, we should NOT need to use "tablets" or do complicated procedures to have clean and good smelling laundry. As I said before, millions of people overseas use FL day in and day out, without doing anything else other than 1) put dirty laundry in 2) select cycle 3) put detergent in 4) push button 5( get clean clothes out. End of the story. Kenmore, Sears, whatever, get your acts together !!

Replace the washer outlet box and drain line. While you're at it, install an intelligent shutoff valve, too: https://www.watts.com/products/plumbing-flow-control-solutions/leak-detection/a2c