Water in hydraulic/transmission fluid

I cleaned up some hydraulic oil a couple years ago by just letting the oil sit in a covered container for about a year. The bottom gallon had water and trash in it but the top 4gal was very clean. I filtered the oil and reused it without any problems.

According to ASTM standards, clean #2 diesel has 500ppm of water content in suspension. You can not see the water in the oil but it's there. At 1000ppm then water falls out of suspension and that is the water you can drain off at the filter drain.

I've never ran into the info on water content of clean ASTM hydraulic oil but the above diesel example should be some what accurate in comparrision.

T_Bone

I needed to do some work on the PTO and decided to drain the rear end oil before removing the PTO shaft. About the first quart of liquid that drained out was water, and the oil was very contaminated. It also appeared to be quite overfull with the added water. I replaced the oil and now keep the top cover covered with canvas, since it had to be rain water getting in the rear end case and the only logical place I could see that it could be doing that is around the spring. No more problems with the hydraulic oil getting milky and I hope the water in the rear end lube didn't do too much damage in that area.

If you retain the milky hydraulic oil in a can, eventually the water mostly settles out to the bottom of the can. I reuse the hydraulic oil after the water settles out. One pretty good way of keeping the water in the settling container is to let it freeze and then to pour the oil into another container, leaving the ice behind.

If you continue to have contamination, you might want to check the rear end. Apparently the seals between the 3 compartments aren't the best, at least on my tractor. Good luck!