It was probably there to protect the tank rubbing against transmission case.<img src="http://www.tractorbynet.com/forums/files/kubota-owning-operating/448528-help-identify-part-img_1370-jpg"/> New owner of a used machine. I was cleaning under the seat of my BX2230 and found this 3/16" thick piece of pliable rubber. It's about 2 1/2" x 1 3/8" . It was sitting under the gas tank on top of what I am guessing is the transmission case. Not sure if it's part of the machine? Any ideas? Thanks