My washer started thumping on spin cycle, and after an internet search I feared the worst- a broken spider arm. Appliance parts pros provided a comprehensive video on how to remove the drum so I could know for sure if my suspicions were correct, and they were.
I ordered a spider arm and 6 bolts, but did not order the drum seal as mine was in good condition. Nor did I order a metal wave washer, which this could prove to be a mistake in the long run, but isn't right now.
This repair was relatively expensive and lengthy, but a new washer would not match our existing dryer, and that would drive me nuts. The spider arm is a common fail point, everything else is in good condition. I expect many more years of service from this washer.