After the washer fills some water into the tub, the flow of water turns off (normal). When the water does turn off, my water pipes make a clanking noise, but not at the washer, rather, at the back of the refrigerator, or possibly under the house (the water pipes to the sink run right below the refrigerator.) This never occurred with my old (12 yrs) Whirlpool top loading washer, but is consistent with the new front loading LG washer.
The installation manual states water supply pressure must be between 14.5-116PSI. I have city water, can't believe it's in excess of 100PSI, but have never measured it, either. Do you think it could need a pressure-reducing valve? Or is it something else? Thanks!

This is classic water hammer. Pipes that are not secure combined with the rapid change in director of water flow when a valve abruptly shuts causes it.

There is cheap meter that you can buy: Amazon.com: Campbell #BTG-100 100 PSI Water Pressure Gauge: Home Improvement (http://www.amazon.com/Campbell-BTG-100-Water-Pressure-Gauge/dp/B000BQN90Q)

You can buy water hammer arrestors to place at the washer. Watts: Water Hammer Arrestors | Water Safety & Flow Control (http://www.watts.com/pro/_products_sub.asp?catId=64&parCat=281)

Sometimes in the walls of your home there are vertical capped pipes. This is a poor man's water arrestor. Draining your water system such that the chambers empty of water and refilling so they fill back up with air sometimes help.

The arrestors should be located near the causes which are typically toilets, dishwashers and washers.