are you printing from word or something?
the page setup defined in word always overrules the driver setting maybe you are facing that issue?
I have two trays on my printer and both are set to 8.5x11 and plain. Tray 1 is always empty and Tray 2 is full. Everytime I print from my windows machine, it auto selects Tray 1 even though I have the printer driver set to autoselect. How can i get my printer to automagically select a tray that's full so that my printer quits telling me to add paper to Tray 1?