I have a L3600 split in my shop at home (brother's tractor) doing the propeller shaft seals.
Has used Traveler fluid in it. I grabbed a bucket and looked at the specs. Kubota does not and has not ever published any specification of their UDT or Super UDT2 fluids. On the Traveler bucket it says "meets kubota spec".....Well....what spec is it?
I work for a dealer and years ago I asked our kubota tech regional guy about propeller shaft seals and why they're common failure points. I was told....cheap fluid....tends to shrink the rubber inside the two collars. Makes sense, every one of them I have done, the collars (or sleeves I guess they really are) aren't really that tight on the shaft, but installing the new ones IS tight. My brother's tractor? The sleeves slid right off by hand with very little effort.
And...have an L2900 split at work, GST clutch discs are garbage. I'm told that traveler doesn't do well with wet clutch linings and sometimes brake linings.
I'm going with sidecarflip on his statement. Cheap is just that. And since I own some equipment and am a working stiff with very little money to spend, I totally understanding saving a dime. However, I also understand you either spend it now, or you spend it later in multiples. It's hard to swallow the price and at the same time I could care less about working on equipment after I get off work, so I spend a little more ahead of time and work a lot less at home.
But at work, I prefer to work on stuff rather than sitting on my fat backside doing nothing, so by all means...dump water or whatever you want in that transmission. Just kidding of course. I'd rather folks never have any problems with their equipment. I can always find something to do.
To drain a little out, loosen the hydraulic filter (not the hst filter)--it is on the RIGHT side (as you are sitting on the tractor) just a little, with bucket under it. Let it just dribble out. Go to the other side and watch the sight window. When it gets to about 3/4, walk back around and tighten the filter, it will continue to drop a little but usually ends up about 1/2 by time you walk back around the tractor. Mind you, you cannot check the fluid level with hot fluid and you cannot check it on unlevel ground. Must be level, must have set at least 1 hour to properly check the level, as it will rise a little as the fluid temp increases and it will fall a little as temp decreases. And finally the fluid tends to get bubbles in it from the froth of being run between all the gears, etc, so you need to let it sit a while before checking the fluid level in the glass.
Lastly, a fluid evactuator works WONDERS for doing what you did, changing the drain bolt, or just changing the filter. BTW the hydraulic filter has a magnet on it already if you didn't know. The evacuator is just another tool that people say they never need, but it is the most important and most used tool that I personally own.