</font><font color="blue" class="small">( THe 10W30 for Kubota is actually not needed. The newer Kubota manuals states a 15W40 is just fine. I called Kubota and that's what they told me anyway. )</font>
My manual lists 10W-30 or 10W-40, but not 15W-40 - though I'm confident there's not enough difference between 10W-40 and 15W-40 to make any discernible difference. /forums/images/graemlins/smile.gif
However, if I'm running my tractor in the winter, I figure I might as well get the lightest weight I can that meets the SAE specs. And, if it's hot enough in the summer that 30 weight isn't going to get the job done, I'm not going to be on the tractor anyway, until it cools down some. /forums/images/graemlins/grin.gif
So, if I can find the 10W-30 without a special trip, I'll use it. But if 15W-40 is what's available, I wouldn't hestitate to use that either. /forums/images/graemlins/smile.gif