Ok, I'll start, especially since this is "my" forum, anyway (Bird's suggestion, not mine.)
Lower speed, heavier duty gears typically use heavier lubricants, with the Kubota front axle gears definitely falling into this category. Some of the newer transmission designs that are very heavy duty require much thinner lubricants than their older counterparts, but these also invariably also require synthetics. The Kubota front axle definitely does not fall into this category. Since Kubota herself (somebody called Kubota "mother" recently, so I'll go along) says you can use either, I opt for the type that is more typically used in this application, the gear oil. Reason: protection. Now, the drawback to the heavier weight oil is circulation. This stuff is very thick in very cold weather - the proverbial comparison to molasses is closer to reality than fantasy in viscosity properties.
So, what to do (most of you knew this was coming)? I use synthetic gear oil because it's low temp viscosity is far lower than its petroleum counterpart's would be. This way, I kill two birds with one stone (sorry, Bird, I couldn't help it...) /w3tcompact/icons/smile.gif.
Mark
