My L35 came with Super UDT fluid in it. I broke a hose on the BH and didn't know it and pumped way too much overboard. Being on the weekend, I bought hdy. oil from Wal Mart (said it met UDT spec on the label) & poured it in. From then on, the GS transmission complained when shifting. I drained all that I could and put UDT back. It doesn't shift as well as before, but better. I plan to put Super UDT Kubota fluid in it the next time I change fluid. My advice is to put Super UDT if you have an HST transmission. It is cheaper than going into the transmission. I'd also put at least Kubota UDT in your tractor if you have a GST. If you have a straight gear shift transmission, then any oil that meets UDT specs should be ok. Good Luck!