Our 2 yr old kenmore Ultradish washer does not clean upper tray items.

Hi! beans3120, welcome to AMHD :)

If you have a fixture in the center of the upper basket that connects to a rotating arm below the upper basket, make sure it is clear of debris, and the arm can rotate freely.

If you hear a rapping noise during a cycle it means the arm is hitting something, either hanging down from the upper basket or standing too tall in the lower, and the arm can't rotate to reach all of the upper basket.
More often the latter, and not the former.

Worst case... The tube that supplies the upper basket fixture is blocked, and needs cleaned.

If you have just a central pyramidal fixture in the lower basket, make sure it isn't blocked from rising, and is clear of debris.

Again, worst case... The tube that supplies the pyramidal fixture is blocked, and needs cleaned.

If you don't have the manual, supply the model # or go here to find one:
managemyhome.com/owner_manuals/search/brand.Kenmore=Dishwasher

See here to locate #, and or search for help on it's site:
partselect.com/repair/appliance=model-number-locator

K