There is no adjustment for fill level, the fill is regulated by time and they assume the water pressure/flow will be at a normal rate to give the correct fill level.
The overfill switch/float should not be activated in normal use.
It is usually just a safety device.

Here are your parts
Pump and motor replacement parts for WHIRLPOOL KUDS230Y2 | AppliancePartsPros.com

Here is the tech sheet
http://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%209741531.pdf

Check to ensure that the unit is not leaving water in the tub after a drain cycle. You may have a partial drain plug. The most common place for this is where the drain hose enters the house plumbing.
Check that the fill valve is not leaking re: it is empty after a wash cycle and then overnight water leaks into the tub.
Check that the drain tube is looped minimum of 10 inches higher than where it enters the house plumbing. Could be it is siphoning water back into the unit or there is a partial house drain plug or it is overflowing back into the unit.
If the unit is attached to an air gap, check/clean it.