Can't say for sure without direct examination or comparison to the sound of the pump on Day 1, but from this position afar, I don't think there's a need to stop using the machine. The sound is very much similar to the pump on my Neptune TL and a friend's Neptune frontloader ... resonating of a pump motor mounted to bottom of the machine's cabinet ... but perhaps a little louder. Unlikely there's a start relay on the pump, they're typically a shaded-pole induction motor. Your choice to call for a service appt for your peace of mind and to confirm if there is/is not a problem. Myself, I'd keep using the machine as-is until the situation gets obviously worse (because it may not) ... as in the pump either leaking or going dead. Or better, I'd break into the machine and examine the pump for evidence of a problem ... but I'm a DIYer and you may not have the ability.

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 !!

And now a follow-up to my March 8, 2017 post: after working flawlessly for ALMOST 3 years, the hammer had returned! Upon the advice of a plumber friend, I removed the arresters and shook whatever water that would come out of them out. I then reinstalled and they quieted things down for about 3 washer loads then the pounding started back up again. I came to the conclusion that the gas charge had failed which was verified by the customer service department at Sioux Chief. I was told to put a pencil, etc into the plunger hole and push - if I met with great resistance, the arrester was OK; if the pencil was able to move the plunger, the charge had been lost. My charge was indeed lost. Since the installation was less that 3 years ago, the warranty kicked in and a new set of 2 is to be mailed to me. I was then advised that because I have a newer, high efficiency washer to install 2 arresters per line to lessen the shock and extend their lives. Long story short, I purchased 2 new arresters and installed them; when the replacements arrive, I'll install them in tandem with the original 2. They had better last longer than 3 years - MUCH longer! BTW, Lowe's pricing has risen from $9.99 ea to $ 12.99 ea today!!

Most of them are copper for copper piping to be soldered on. They do make the ones that just attach to the faucet threads. They would mount as close as possible to the source of the hammering (the washer threads) but can't always get to that access. Mounting them at the faucet should work OK. Most mount on the 'UP' position, some can be mounted any position. One for each hose. http://www.factsfacts.com/MyHomeRepair/PipeNoises.htm then "water hammer arresters" link on the 3rd or 4th paragraph. You could use the one in the TOP RIGHT picture. http://www.homedepotmoving.com/proj_article_page.do?action=GetProjArtcilePage&projId=150 Here is a link that might be useful: Washing Machine arrester @ Lowes $10.45