do a search for your appliance schematic so you can find part numbers.. once you have the numbers you can find videos here on appliancepartspros.com..

the first thing to check if there is thumping on spin cycle are the tub springs.. make sure they're all attached.. if they're worn you may want to replace them.. also check the back balance spring.. it's longer and hooks to the bottom frame..

if your spin cycle isn't going as fast as it should.. this is most likely a worn clutch.. the pads wear off over time and it's like a car.. you rev the engine and try to engage the clutch but you have to wait to pick up speed as the worn clutch catches... same thing.. so this is most likely the problem you have.. you probably need a new clutch assembly.. it's basically the same price as the pad and spring part alone so just get the entire assembly.. it also comes with a brake cam driver.