Normally there is only one main part the pump. It either is pushing water up to arms or out to the drain. There is also a water valve and one that operates which way the pump pumps. In the bottom under the arm there is a filter some are removable some are fixed. Look at the spray holes in the arms for blockage mainly on the ends of the arms.Need to know the brand and model number. Can also look at parts breakdown might help by going onto a appliance parts company and enter brand and model. Look at the pump assembly. Within the first minute of pushing start the water valve opens fills the bottom turns on the pump if the noise starts in the first minute sounds like the fill water valve. Water valve is in the front under kick plate.