Yea, I have been telling people this for years, [and getting flamed on here a few times also]. Most new oils are not filtered unless they are the high hour and high $$$ oils. You want something really scary look in the bottom of a barrel of 2000 hour oil. Dirt, specs of metal and some sort of fiber were all in the mix. Companys will literally spend 10's of thousands of dollars on Hydrostatic systems but some are too cheap to filter the oil that they are putting in, even if you prove to them it is dirty. Schramm water well rigs now have a filtered transfer pump for adding hydraulic oil to their systems because of dirt I would imagine??? I have had a few completely new Hydrostatic systems shut down within a week because of a dirty charge filter, I attribute at least some of them to dirty new oil all the systems we build are cleaned out including the hoses. The only variable is the oil. All of our tranfer pumps have 10 micron filters and the filter carts I build have a 10 and a 3 micron on them. CJ