There is all sorts of stuff on the web in forums and videos that talk about the 50 hr filter change with or without a fluid change. As I understand the manual, at 50, you change both the transmission (the short one) and the hydraulic (the longer one with the magnet in it) oil filters at 50, but you do not change the fluid until 400. So you can either change the fluid to be on the safe side and spend the extra bucks for the fluid, or you can try to change filters without draining the fluid. The shop vac method seems to be the most often used. Parking it on a slope is another. The manual tells you to replace the transmission filter without messing with a fluid change and it says do NOT remove the hydraulic filter or the oil will drain out, therefore implying that you can change the transmission filter with no fuss, but the hydraulic filter is another matter. My take is that both the hydraulic implements and the HST transmission take the fluid from a single reservoir, which is part of the reason for the 11+ gallon capacity. If you want to do both filters without either changing the fluid or trapping it in a clean container and putting it back in after the filter change, you are stuck with something like the shop vac approach. I just finished changing both filters without doing a fluid change and this was my experience:
- I parked the tractor on a 3.5 degree slope with the front of the tractor uphill. The slope was measured with a Fowler MiniMag electronic Protractor attached to the "H" shaped machined flat on the bottom of the casting (middle of tractor just forward of the two filters).
- I attached a Shop Vac to the fill port, but did not use it when I changed the transmission filter. I lost very little fluid (other than what was in the filter itself) even without the Shop Vac. I did have a bit of trouble getting the filter broken loose because it was extremely tight. I suspect some of that problem might be due to the use of an o-ring seal instead of the usual square cross section gasket, so the o-ring crush may result in metal to metal contact when you really torque down on it like they apparently do at the factory and you end up needing some elbow grease to break it loose.
- The longer filter ("hydraulic") was easier to break loose. I unscrewed it until I started getting a little fluid, then turned on the Shop Vac and left it on until I had the new filter screwed on enough for the gasket to contact finger tight. Then I turned the Shop Vac off. Again, I lost almost no fluid except for what was in the old filter. Honestly, I don't know whether the Shop Vac or parking on a slope made the difference. If someone plans to change the fluid, it might be worthwhile to park it on a slope and see what happens when you take the filter off without draining the fluid first and report results back to the forum. There was no oil in the Vac hose nozzle that I could tell and the fact that the filter was pretty much full of fluid tells you that the concern mentioned on other sites about pulling dirty fluid out of the filter back up into the hydraulic system is pretty much not a concern as far as I can tell. You'd need a very powerful vacuum and would need to have no air leakage through the dip stick or anywhere else in the system in order to pull fluid up out of the filter and into the vac. The magnet had a lot of metal particles stuck to it, so I am glad that I went ahead and changed it.
- I found the manual terminology a little confusing. They refer to "Transmission Oil Filter (HST Type)" and "Replacing Hydraulic Oil Filter". As far as I can tell, both of these filters are hydraulic oil filters and use fluid from the same tank on the low pressure side of the system, it's just that one of them primarily services the HST transmission and the other services the general hydraulic system. The magnet is a good approach that is used in other systems, but I was a bit surprised at how much material was on the magnet after only 54 hours of use since new. For that reason, I would say it is worthwhile to change the filter at 50 and do not wait until 400 to do the first filter change.
- The space between the two filters means you really need a metal strap filter wrench. A chain type will not work and it's unlikely that the plier type will work either. At some point, you will have problems loosening or tightening the filter by hand or with the wrench because everything will be too slick with oil. If you buy a can of industrial hand wipes, the kind that you use without water, but they are moistened and have some texture to them (e.g. LPS, Fast Orange, Scrubs), you can probably keep the filter, your hands/gloves, and the filter wrench clean enough to grip and turn the filter as you go.
