I too have had this problem many many times, beginning at pretty much the same time AFTER the warranty was up, less then 40 days. I even had to have the entire tub motor and related parts replaced and whirlpool refused to honor the warranty because it was 7 days after the warranty. I called Whirlpool Corporate and the nicest woman on the planet honored the warranty and had a the repair shop come and pick it up in less than 24 hours. Got it back and it ran great for a month then began the F28 all over again... ...On this machine you must remove the lower front panel by removing the three 1/4" screws from bottom, reach up the right side of the machine find the plastic tab dangling there and give it a pull and the door comes open. THERE IS NO LEVER ANYWHERE NEAR THE SOAP TRAY.
Now I will try the cleaning of the contacts. If this works I will be amazed, if it remedies the recurring problem I will be happy and amazed. If it does not. I will dump the machine and buy a samsung and NEVER purchase a Whirlpool or any other product they are associated with.
Elmo Thursby, September 2010