My unit is a 555 and as I stated when I first joined, I use the hell out of it. I probably should just pony up and get a new unit but I am a cheap SOB so I won't. Last night, when I went to start the unit I noticed white fluid under it. Most probably from a hydraulic leak and I have water in the fluid. I always fire the unit up and it idles for 15 minutes to 30 mintues before I get around to using it. Partly because I have other stuff that needs to get done and partly becasue I have noticed that when it is really cold like it has been (5 with the wind chill this AM), that the boom does not move fast enough. If I wait, the boom moves just fine. Anyway, after I had used the unit for about 5 minutes, I went to pick up a round bale and my boom got stuck. It stopped in one position and I could not move. The pedals appeared to be operating the boom slighty in the opposite direction of what they should be doing. After not touching the pedals for a couple of minutes I would get the boom back briefly, enough to spear the bale and pick it up. I then would take it to the pasture and I would have the boom moving correcting to drop the bale but I could not do much beyond that. So my question is: Knowing without a doubt that I have water in the hyro oil and this casued the probelm, I plan on draining the oil out tonight. I have heard people talk about using 10W 30 engine oil (diesel oil?) instead of hydry fluild. Can I do this with my unit? I modified my cylinder that runs the bucket on this unit. The 555 only came with ONE cylinder on the bucket and I constantly was braking it so I mounted two mounting brackets on the boom and on the attachment plate and now run two cylinders, similar to newer units. This added to the capacity though on the hydro fluid and it now takes about 17 gallons to completly fill. It is pretty expensive to use the hyrdo oil as a result so if I can get away with 10W 30 oil that would be great. Thanks....this board has saved my ass multiple times in the past year.