I would look at the shufoffs.
If there is a loose washer it will vibrate while filling, creating noise and hammer. A hammer arrestor normally is usefull only when the washer shuts off, not while filling.
I have an LG washing machine. On a cycle that draws hot water the water hammer is really really loud. I am concerned about damage to the copper pipes the noise and rattling is so bad.
I tried a sioux chief mini-rester - that did not really help. Next a watts arrestor (the blue one - a little smaller than a baseball) at the hot water shut off for the washing machine. It sort of helped the first time we ran the machine, but the next time the slamming was back.
Should we just junk the washer? is there any way to fix this (at this point if we have to break open the walls I am game for that). Should the arrestors go right in the back of the washer and not be at the shutoff?