My Whirlpool duet washer is making very loud noises on the spin cycle - it still drains and spins but the spin is uneven and sounds like there is something grinding inside. The spin does not seem to be as good as it previously was. What could this be?

VERY loud noises might indicate a loose counter weight. Open the cabinet then raise the top and check the condition of the counterweights and that they are fastened down properly. The front lower counterweight is held on at the ends by two lugs connected by a formed rebar rod and a spaced bolt in the middle of it. Check these first. Loose you can fix. If the rebar breaks, the counterweight will beat the inside of the machine up pretty good, usually damaging the water pump strainer housing. If this doesn't solve your problem, look at some of the other posts here for other ideas. They're really good.
Regards, --WoobieDog--