Be prepared to invent new words when changing the fuel filters. There are 2 of them. The "easy" way is to remove the battery, then the battery box, get 'em out of the way. The "hard" way, do it with the battery still installed. Neither is tough but Kubota seems to like to make fuel filters less than ideally accessible; except on the newer ZD-11 series, which are MUCH easier.
Getting under it to drain the engine and trans oil can be a chore. I usually lift the tractor up and put it on stands. Makes things go a lot easier.
When you're ready to do the transmission, remove all 3 drain bolts and drain the brake cases AND center case. Refill with super udt2 ONLY. I keep seeing and hearing of folks who are having hydraulic and transmission issues, and most of them cheaped out with non-SUDT2, and get to pay the price; and most of the time they repair the problem and put the junk right back in. Didn't learn?
I was at TSC the other day looking at hydrualic fluids. One bucket said "meets Kubota specification"....specification for what? The bucket? Yeah it comes in a 5 gal bucket too. The stuff is super thick, smells like aircraft fuel. I have it in my old tractor (came with it...MF 1145), and yeah, it's thick alright. Fire up the tractor on a cold day, and wait until it warms up enough to flow. Slow loader, can hear the pump pulling the engine down, etc. But Super UDT2 has never showed those issues. HST's run quieter, hydraulic systems work better, etc, cold AND hot. Depending on where you live, hot can be an issue-especially with the ZD series. We used to have to put many HST's in the old ZD21/25/28 mowers--at $1300 a pop-because of 2 reasons. Junk fluid and lack of maintenance. They ran hot. The ZD300 series addressed the biggest part of the problem but they aren't totally out of the woods. Hot climates need the fluid and filters changed more often just as dusty climates need air filters changed more often.